IEEE Std 1159-1995 IEEE Recommended Practice for Monitoring Electric Power Quality
Sponsor
IEEE Standards Coordinating Committee 22 on
Power Quality
Approved June 14, 1995
IEEE Standards Board
Abstract: The monitoring of electric power quality of ac power systems, definitions of power quality terminology, impact of poor power quality on utility and customer equipment, and the measurement of electromagnetic phenomena are covered.
Keywords: data interpretation, electric power quality, electromagnetic phenomena, monitoring, power quality definitions
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Introduction
(This introduction is not part of IEEE Std 1159-1995, IEEE Recommended Practice for Monitoring Electric Power Quality.)
This recommended practice was developed out of an increasing awareness of the difTculty in comparing results obtained by researchers using different instruments when seeking to characterize the quality of low-voltage power systems. One of the initial goals was to promote more uniformity in the basic algorithms and data reduction methods applied by different instrument manufacturers. This proved difTcult and was not achieved, given the free market principles under which manufacturers design and market their products. However, consensus was achieved on the contents of this recommended practice, which provides guidance to users of monitoring instruments so that some degree of comparisons might be possible.
An important Trst step was to compile a list of power quality related deTnitions to ensure that contributing parties would at least speak the same language, and to provide instrument manufacturers with a common base for identifying power quality phenomena. From that starting point, a review of the objectives of moni-toring provides the necessary perspective, leading to a better understanding of the means of monitoring?the instruments. The operating principles and the application techniques of the monitoring instruments are described, together with the concerns about interpretation of the monitoring results. Supporting information is provided in a bibliography, and informative annexes address calibration issues.
The Working Group on Monitoring Electric Power Quality, which undertook the development of this recom-mended practice, had the following membership:
J. Charles Smith, Chair Gil Hensley, Secretary
Larry Ray, Technical Editor
Mark Andresen Thomas Key John Roberts
Vladi Basch Jack King Anthony St. John
Roger Bergeron David Kreiss Marek Samotyj
John Burnett Fran?ois Martzloff Ron Smith
John Dalton Alex McEachern Bill Stuntz
Andrew Dettloff Bill Moncrief John Sullivan
Dave GrifTth Allen Morinec David Vannoy
Thomas Gruzs Ram Mukherji Marek Waclawlak
Erich Gunther Richard Nailen Daniel Ward
Mark Kempker David Pileggi Steve Whisenant
Harry Rauworth
In addition to the working group members, the following people contributed their knowledge and experience to this document:
Ed Cantwell Christy Herig Tejindar Singh
John Curlett Allan Ludbrook Maurice Tetreault
Harshad Mehta
iii
The following persons were on the balloting committee:
James J. Burke David Kreiss Jacob A. Roiz
David A. Dini Michael Z. Lowenstein Marek Samotyj
W. Mack Grady Fran?ois D. Martzloff Ralph M. Showers
David P. Hartmann Stephen McCluer J. C. Smith
Michael Higgins A. McEachern Robert L. Smith
Thomas S. Key W. A. Moncrief Daniel J. Ward
Joseph L. KoepTnger P. Richman Charles H. Williams
John M. Roberts
When the IEEE Standards Board approved this standard on June 14, 1995, it had the following membership:
E. G. òAló Kiener, Chair Donald C. Loughry,Vice Chair
Andrew G. Salem,Secretary
Gilles A. Baril Richard J. Holleman Marco W. Migliaro
Clyde R. Camp Jim Isaak Mary Lou Padgett
Joseph A. Cannatelli Ben C. Johnson John W. Pope
Stephen L. Diamond Sonny Kasturi Arthur K. Reilly
Harold E. Epstein Lorraine C. Kevra Gary S. Robinson
Donald C. Fleckenstein Ivor N. Knight Ingo Rusch
Jay Forster*Joseph L. KoepTnger*Chee Kiow Tan
Donald N. Heirman D. N. òJimó Logothetis Leonard L. Tripp
L. Bruce McClung
*Member Emeritus
Also included are the following nonvoting IEEE Standards Board liaisons:
Satish K. Aggarwal
Richard B. Engelman
Robert E. Hebner
Chester C. Taylor
Rochelle L. Stern
IEEE Standards Project Editor
iv
Contents
CLAUSE PAGE 1.Overview (1)
1.1Scope (1)
1.2Purpose (2)
2.References (2)
3.Definitions (2)
3.1Terms used in this recommended practice (2)
3.2Avoided terms (7)
3.3Abbreviations and acronyms (8)
4.Power quality phenomena (9)
4.1Introduction (9)
4.2Electromagnetic compatibility (9)
4.3General classification of phenomena (9)
4.4Detailed descriptions of phenomena (11)
5.Monitoring objectives (24)
5.1Introduction (24)
5.2Need for monitoring power quality (25)
5.3Equipment tolerances and effects of disturbances on equipment (25)
5.4Equipment types (25)
5.5Effect on equipment by phenomena type (26)
6.Measurement instruments (29)
6.1Introduction (29)
6.2AC voltage measurements (29)
6.3AC current measurements (30)
6.4Voltage and current considerations (30)
6.5Monitoring instruments (31)
6.6Instrument power (34)
7.Application techniques (35)
7.1Safety (35)
7.2Monitoring location (38)
7.3Equipment connection (41)
7.4Monitoring thresholds (43)
7.5Monitoring period (46)
8.Interpreting power monitoring results (47)
8.1Introduction (47)
8.2Interpreting data summaries (48)
8.3Critical data extraction (49)
8.4Interpreting critical events (51)
8.5Verifying data interpretation (59)
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ANNEXES PAGE Annex A Calibration and self testing (informative) (60)
A.1Introduction (60)
A.2Calibration issues (61)
Annex B Bibliography (informative) (63)
B.1Definitions and general (63)
B.2Susceptibility and symptoms?voltage disturbances and harmonics (65)
B.3Solutions (65)
B.4Existing power quality standards (67)
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IEEE Recommended Practice for Monitoring Electric Power Quality
1. Overview
1.1 Scope
This recommended practice encompasses the monitoring of electric power quality of single-phase and polyphase ac power systems. As such, it includes consistent descriptions of electromagnetic phenomena occurring on power systems. The document also presents deTnitions of nominal conditions and of deviations from these nominal conditions, which may originate within the source of supply or load equipment, or from interactions between the source and the load.
Brief, generic descriptions of load susceptibility to deviations from nominal conditions are presented to identify which deviations may be of interest. Also, this document presents recommendations for measure-ment techniques, application techniques, and interpretation of monitoring results so that comparable results from monitoring surveys performed with different instruments can be correlated.
While there is no implied limitation on the voltage rating of the power system being monitored, signal inputs to the instruments are limited to 1000 Vac rms or less. The frequency ratings of the ac power systems being monitored are in the range of 45D450 Hz.
Although it is recognized that the instruments may also be used for monitoring dc supply systems or data transmission systems, details of application to these special cases are under consideration and are not included in the scope. It is also recognized that the instruments may perform monitoring functions for envi-ronmental conditions (temperature, humidity, high frequency electromagnetic radiation); however, the scope of this document is limited to conducted electrical parameters derived from voltage or current measure-ments, or both.
Finally, the deTnitions are solely intended to characterize common electromagnetic phenomena to facilitate communication between various sectors of the power quality community. The deTnitions of electromagnetic phenomena summarized in table 2 are not intended to represent performance standards or equipment toler-ances. Suppliers of electricity may utilize different thresholds for voltage supply, for example, than the ±10% that deTnes conditions of overvoltage or undervoltage in table 2. Further, sensitive equipment may mal-function due to electromagnetic phenomena not outside the thresholds of the table 2 criteria.
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IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR 1.2 Purpose
The purpose of this recommended practice is to direct users in the proper monitoring and data interpretation of electromagnetic phenomena that cause power quality problems. It deTnes power quality phenomena in order to facilitate communication within the power quality community. This document also forms the con-sensus opinion about safe and acceptable methods for monitoring electric power systems and interpreting the results. It further offers a tutorial on power system disturbances and their common causes.
2. References
This recommended practice shall be used in conjunction with the following publications. When the follow-ing standards are superseded by an approved revision, the revision shall apply.
IEC 1000-2-1 (1990), Electromagnetic Compatibility (EMC)?Part 2 Environment. Section 1: Description of the environment?electromagnetic environment for low-frequency conducted disturbances and signaling in public power supply systems.1
IEC 50(161)(1990), International Electrotechnical V ocabulary?Chapter 161: Electromagnetic Compatibility. IEEE Std 100-1992, IEEE Standard Dictionary of Electrical and Electronic Terms (ANSI).2
IEEE Std 1100-1992, IEEE Recommended Practice for Powering and Grounding Sensitive Electronic Equipment (Emerald Book) (ANSI).
3. DeTnitions
The purpose of this clause is to present concise deTnitions of words that convey the basic concepts of power quality monitoring. These terms are listed below and are expanded in clause 4. The power quality commu-nity is also pervaded by terms that have no scientiTc deTnition. A partial listing of these words is included in 3.2; use of these terms in the power quality community is discouraged. Abbreviations and acronyms that are employed throughout this recommended practice are listed in 3.3.
3.1 Terms used in this recommended practice
The primary sources for terms used are IEEE Std 100-19923 indicated by (a), and IEC 50 (161)(1990) indi-cated by (b). Secondary sources are IEEE Std 1100-1992 indicated by (c), IEC-1000-2-1 (1990) indicated by (d) and UIE -DWG-3-92-G [B16]4. Some referenced deTnitions have been adapted and modiTed in order to apply to the context of this recommended practice.
3.1.1 accuracy: The freedom from error of a measurement. Generally expressed (perhaps erroneously) as percent inaccuracy. Instrument accuracy is expressed in terms of its uncertainty?the degree of deviation from a known value. An instrument with an uncertainty of 0.1% is 99.9% accurate. At higher accuracy lev-els, uncertainty is typically expressed in parts per million (ppm) rather than as a percentage.
1IEC publications are available from IEC Sales Department, Case Postale 131, 3, rue de Varemb?, CH-1211, Gen?ve 20, Switzerland/ Suisse. IEC publications are also available in the United States from the Sales Department, American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA.
2IEEE publications are available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331, USA.
3Information on references can be found in clause 2.
4The numbers in brackets correspond to those bibliographical items listed in annex B.
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IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995 3.1.2 accuracy ratio: The ratio of an instrument?s tolerable error to the uncertainty of the standard used to calibrate it.
3.1.3 calibration: Any process used to verify the integrity of a measurement. The process involves compar-ing a measuring instrument to a well defined standard of greater accuracy (a calibrator) to detect any varia-tions from specified performance parameters, and making any needed compensations. The results are then recorded and filed to establish the integrity of the calibrated instrument.
3.1.4 common mode voltage: A voltage that appears between current-carrying conductors and ground.b The noise voltage that appears equally and in phase from each current-carrying conductor to ground.c
3.1.5 commercial power: Electrical power furnished by the electric power utility company.c
3.1.6 coupling: Circuit element or elements, or network, that may be considered common to the input mesh and the output mesh and through which energy may be transferred from one to the other.a
3.1.7 current transformer (CT): An instrument transformer intended to have its primary winding con-nected in series with the conductor carrying the current to be measured or controlled.a
3.1.8 dip: See: sag.
3.1.9 dropout: A loss of equipment operation (discrete data signals) due to noise, sag, or interruption.c
3.1.10 dropout voltage: The voltage at which a device fails to operate.c
3.1.11 electromagnetic compatibility: The ability of a device, equipment, or system to function satisfacto-rily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to any-thing in that environment.b
3.1.12 electromagnetic disturbance: Any electromagnetic phenomena that may degrade the performance of a device, equipment, or system, or adversely affect living or inert matter.b
3.1.13 electromagnetic environment: The totality of electromagnetic phenomena existing at a given location.b
3.1.14 electromagnetic susceptibility: The inability of a device, equipment, or system to perform without degradation in the presence of an electromagnetic disturbance.
NOTE?Susceptibility is a lack of immunity.b
3.1.15 equipment grounding conductor: The conductor used to connect the noncurrent-carrying parts of conduits, raceways, and equipment enclosures to the grounded conductor (neutral) and the grounding elec-trode at the service equipment (main panel) or secondary of a separately derived system (e.g., isolation transformer). See Section 100 in ANSI/NFPA 70-1993 [B2].
3.1.16 failure mode: The effect by which failure is observed.a
3.1.17 ?icker: Impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time.b
3.1.18 frequency deviation: An increase or decrease in the power frequency. The duration of a frequency deviation can be from several cycles to several hours.c Syn.: power frequency variation.
3.1.19 fundamental (component): The component of an order 1 (50 or 60 Hz) of the Fourier series of a periodic quantity.b
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IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR 3.1.20 ground: A conducting connection, whether intentional or accidental, by which an electric circuit or piece of equipment is connected to the earth, or to some conducting body of relatively large extent that serves in place of the earth.
NOTE? It is used for establishing and maintaining the potential of the earth (or of the conducting body) or approxi-mately that potential, on conductors connected to it, and for conducting ground currents to and from earth (or the con-ducting body).a
3.1.21 ground loop: In a radial grounding system, an undesired conducting path between two conductive bodies that are already connected to a common (single-point) ground.
3.1.22 harmonic (component): A component of order greater than one of the Fourier series of a periodic quantity.b
3.1.23 harmonic content: The quantity obtained by subtracting the fundamental component from an alter-nating quantity.a
3.1.24 immunity (to a disturbance): The ability of a device, equipment, or system to perform without deg-radation in the presence of an electromagnetic disturbance.b
3.1.25 impulse: A pulse that, for a given application, approximates a unit pulse.b When used in relation to the monitoring of power quality, it is preferred to use the term impulsive transient in place of impulse.
3.1.26 impulsive transient: A sudden nonpower frequency change in the steady-state condition of voltage or current that is unidirectional in polarity (primarily either positive or negative).
3.1.27 instantaneous: A time range from 0.5D30 cycles of the power frequency when used to quantify the duration of a short duration variation as a modifier.
3.1.28 interharmonic (component): A frequency component of a periodic quantity that is not an integer multiple of the frequency at which the supply system is designed to operate operating (e.g., 50 Hz or 60 Hz).
3.1.29 interruption, momentary (power quality monitoring): A type of short duration variation. The complete loss of voltage (< 0.1 pu) on one or more phase conductors for a time period between 0.5 cycles and 3 s.
3.1.30 interruption, sustained (electric power systems): Any interruption not classified as a momentary interruption.
3.1.31 interruption, temporary (power quality monitoring):A type of short duration variation. The com-plete loss of voltage (< 0.1 pu) on one or more phase conductors for a time period between 3 s and 1 min.
3.1.32 isolated ground: An insulated equipment grounding conductor run in the same conduit or raceway as the supply conductors. This conductor may be insulated from the metallic raceway and all ground points throughout its length. It originates at an isolated ground-type receptacle or equipment input terminal block and terminates at the point where neutral and ground are bonded at the power source. See Section 250-74, Exception #4 and Exception in Section 250-75 in ANSI/NFPA 70-1993 [B2].
3.1.33 isolation: Separation of one section of a system from undesired influences of other sections.c
3.1.34 long duration voltage variation:See: voltage variation, long duration.
3.1.35 momentary (power quality monitoring): A time range at the power frequency from 30 cycles to 3 s when used to quantify the duration of a short duration variation as a modifier.
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IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995 3.1.36 momentary interruption:See: interruption, momentary.
3.1.37 noise: Unwanted electrical signals which produce undesirable effects in the circuits of the control systems in which they occur.a (For this document, control systems is intended to include sensitive electronic equipment in total or in part.)
3.1.38 nominal voltage (Vn): A nominal value assigned to a circuit or system for the purpose of conve-niently designating its voltage class (as 120/208208/120, 480/277, 600).d
3.1.39 nonlinear load: Steady-state electrical load that draws current discontinuously or whose impedance varies throughout the cycle of the input ac voltage waveform.c
3.1.40 normal mode voltage: A voltage that appears between or among active circuit conductors, but not between the grounding conductor and the active circuit conductors.
3.1.41 notch: A switching (or other) disturbance of the normal power voltage waveform, lasting less than 0.5 cycles, which is initially of opposite polarity than the waveform and is thus subtracted from the normal waveform in terms of the peak value of the disturbance voltage. This includes complete loss of voltage for up to 0.5 cycles [B13].
3.1.42 oscillatory transient: A sudden, nonpower frequency change in the steady-state condition of voltage or current that includes both positive or negative polarity value.
3.1.43 overvoltage: When used to describe a specific type of long duration variation, refers to a measured voltage having a value greater than the nominal voltage for a period of time greater than 1 min. Typical val-ues are 1.1D1.2 pu.
3.1.44 phase shift: The displacement in time of one waveform relative to another of the same frequency and harmonic content.c
3.1.45 potential transformer (PT): An instrument transformer intended to have its primary winding con-nected in shunt with a power-supply circuit, the voltage of which is to be measured or controlled. Syn.: volt-age transformer.a
3.1.46 power disturbance: Any deviation from the nominal value (or from some selected thresholds based on load tolerance) of the input ac power characteristics.c
3.1.47 power quality: The concept of powering and grounding sensitive equipment in a manner that is suit-able to the operation of that equipment.c
NOTE?Within the industry, alternate definitions or interpretations of power quality have been used, reflecting different points of view. Therefore, this definition might not be exclusive, pending development of a broader consensus.
3.1.48 precision: Freedom from random error.
3.1.49 pulse: An abrupt variation of short duration of a physical an electrical quantity followed by a rapid return to the initial value.
3.1.50 random error: Error that is not repeatable, i.e., noise or sensitivity to changing environmental factors. NOTE?For most measurements, the random error is small compared to the instrument tolerance.
3.1.51 sag: A decrease to between 0.1 and 0.9 pu in rms voltage or current at the power frequency for dura-tions of 0.5 cycle to 1 min. Typical values are 0.1 to 0.9 pu.b See: dip.
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IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR NOTE?To give a numerical value to a sag, the recommended usage is òa sag to 20%,ó which means that the line volt-age is reduced down to 20% of the normal value, not reduced by 20%. Using the preposition òofó (as in òa sag of 20%,óor implied by òa 20% sagó) is deprecated.
3.1.52 shield: A conductive sheath (usually metallic) normally applied to instrumentation cables, over the insulation of a conductor or conductors, for the purpose of providing means to reduce coupling between the conductors so shielded and other conductors that may be susceptible to, or that may be generating unwanted electrostatic or electromagnetic fields (noise).c
3.1.53 shielding: The use of a conducting and/or ferromagnetic barrier between a potentially disturbing noise source and sensitive circuitry. Shields are used to protect cables (data and power) and electronic cir-cuits. They may be in the form of metal barriers, enclosures, or wrappings around source circuits and receiv-ing circuits.c
3.1.54 short duration voltage variation:See: voltage variation, short duration.
3.1.55 slew rate: Rate of change of ac voltage, expressed in volts per second a quantity such as volts, fre-quency, or temperature.a
3.1.56 sustained: When used to quantify the duration of a voltage interruption, refers to the time frame asso-ciated with a long duration variation (i.e., greater than 1 min).
3.1.57 swell: An increase in rms voltage or current at the power frequency for durations from 0.5 cycles to 1 min. Typical values are 1.1D1.8 pu.
3.1.58 systematic error: The portion of error that is repeatable, i.e., zero error, gain or scale error, and lin-earity error.
3.1.59 temporary interruption:See: interruption, temporary.
3.1.60 tolerance: The allowable variation from a nominal value.
3.1.61 total harmonic distortion disturbance level: The level of a given electromagnetic disturbance caused by the superposition of the emission of all pieces of equipment in a given system.b The ratio of the rms of the harmonic content to the rms value of the fundamental quantity, expressed as a percent of the fun-damental [B13].a Syn.: distortion factor.
3.1.62 traceability: Ability to compare a calibration device to a standard of even higher accuracy. That stan-dard is compared to another, until eventually a comparison is made to a national standards laboratory. This process is referred to as a chain of traceability.
3.1.63 transient: Pertaining to or designating a phenomenon or a quantity that varies between two consecu-tive steady states during a time interval that is short compared to the time scale of interest. A transient can be a unidirectional impulse of either polarity or a damped oscillatory wave with the first peak occurring in either polarity.b
3.1.64 undervoltage: A measured voltage having a value less than the nominal voltage for a period of time greater than 1 min when used to describe a specific type of long duration variation, refers to. Typical values are 0.8D0.9 pu.
3.1.65 voltage change: A variation of the rms or peak value of a voltage between two consecutive levels sustained for definite but unspecified durations.d
3.1.66 voltage dip:See: sag.
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IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995 3.1.67 voltage distortion: Any deviation from the nominal sine wave form of the ac line voltage.
3.1.68 voltage ?uctuation: A series of voltage changes or a cyclical variation of the voltage envelope.d
3.1.69 voltage imbalance (unbalance), polyphase systems: The maximum deviation among the three phases from the average three-phase voltage divided by the average three-phase voltage. The ratio of the neg-ative or zero sequence component to the positive sequence component, usually expressed as a percentage.a
3.1.70 voltage interruption: Disappearance of the supply voltage on one or more phases. Usually qualified by an additional term indicating the duration of the interruption (e.g., momentary, temporary, or sustained).
3.1.71 voltage regulation: The degree of control or stability of the rms voltage at the load. Often specified in relation to other parameters, such as input-voltage changes, load changes, or temperature changes.c
3.1.72 voltage variation, long duration: A variation of the rms value of the voltage from nominal voltage for a time greater than 1 min. Usually further described using a modifier indicating the magnitude of a volt-age variation (e.g., undervoltage, overvoltage, or voltage interruption).
3.1.73 voltage variation, short duration: A variation of the rms value of the voltage from nominal voltage for a time greater than 0.5 cycles of the power frequency but less than or equal to 1 minute. Usually further described using a modifier indicating the magnitude of a voltage variation (e.g. sag, swell, or interruption) and possibly a modifier indicating the duration of the variation (e.g., instantaneous, momentary, or temporary).
3.1.74 waveform distortion: A steady-state deviation from an ideal sine wave of power frequency princi-pally characterized by the spectral content of the deviation [B13].
3.2 Avoided terms
The following terms have a varied history of usage, and some may have speciTc deTnitions for other appli-cations. It is an objective of this recommended practice that the following ambiguous words not be used in relation to the measurement of power quality phenomena:
blackout frequency shift
blink glitch
brownout (see 4.4.3.2)interruption (when not further qualiTed)
bump outage (see 4.4.3.3)
clean ground power surge
clean power raw power
computer grade ground raw utility power
counterpoise ground shared ground
dedicated ground spike
dirty ground subcycle outages
dirty power surge (see 4.4.1)
wink
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IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR 3.3 Abbreviations and acronyms
The following abbreviations and acronyms are used throughout this recommended practice:
3.3.1 A: amperes
3.3.2 ac: alternating current
3.3.3 ASD: adjustable speed drive
3.3.4 CRT: cathode-ray tube
3.3.5 CT: current transformer
3.3.6 CVT: constant voltage transformer
3.3.7 dc: direct current
3.3.8 DMM: digital multimeter
3.3.9 DVM: digital voltmeter
3.3.10 EFT: electrical fast transient
3.3.11 EMC: electromagnetic compatibility
3.3.12 emf: electromotive force
3.3.13 EMF: electromagnetic Teld
3.3.14 EMI: electromagnetic interference
3.3.15 ESD: electrostatic discharge
3.3.16 Hz: hertz; cycles per second
3.3.17 LC: inductor-capacitor
3.3.18 MOV: metal-oxide varistor
3.3.19 MCOV: maximum continuous operating voltage
3.3.20 MTBF: mean time between failures
3.3.21 NEMP: nuclear electromagnetic pulse
3.3.22 PC: personal computer
3.3.23 PLC: programmable logic controller
3.3.24 PT: potential transformer
3.3.25 RAM: random-access memory
3.3.26 RFI: radio-frequency interference
3.3.27 rms: root-mean-square (effective value)
3.3.28 RVM: recording voltmeter
3.3.29 SCR: silicon-controlled rectiTer
3.3.30 SPD: surge-protective device
3.3.31 THD: total harmonic distortion
3.3.32 TVSS: transient voltage surge suppressor
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IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995 3.3.33 UPS: uninterruptible power supply
3.3.34 V: volts
3.3.35 VOM: volt-ohm meter
4. Power quality phenomena
4.1 Introduction
The term power quality refers to a wide variety of electromagnetic phenomena that characterize the voltage and current at a given time and at a given location on the power system. This clause expands on the deTni-tions of clause 3 by providing technical descriptions and examples of the principal electromagnetic phenom-ena causing power quality problems.
The increasing application of electronic equipment that can cause electromagnetic disturbances, or that can be sensitive to these phenomena, has heightened the interest in power quality in recent years. Accompanying the increase in operation problems have been a variety of attempts to describe the phenomena. Unfortu-nately, different segments of the electronics community have utilized different terminologies to describe electromagnetic events. This clause expands the terminology that will be used in the power quality commu-nity to describe these common events. This clause also offers explanations as to why commonly used termi-nology in other communities will not be used in power quality discussions.
4.2 Electromagnetic compatibility
This document uses the electromagnetic compatibility approach to describing power quality phenomena. The electromagnetic compatibility approach has been accepted by the international community in IEC stan-dards produced by IEC Technical Committee 77. The reader is referred to clause 3 for the deTnition of elec-tromagnetic compatibility and related terms. Reference [B16] provides an excellent overview of the electromagnetic compatibility concept and associated IEC documents.
4.3 General classiTcation of phenomena
The IEC classiTes electromagnetic phenomena into several groups as shown in table 1 [B10]. The IEC stan-dard addresses the conducted electrical parameters shown in table 1. The terms high- and low-frequency are not deTned in terms of a speciTc frequency range, but instead are intended to indicate the relative difference in principal frequency content of the phenomena listed in these categories.
This recommended practice contains a few additional terms related to the IEC terminology. The term sag is used in the power quality community as a synonym to the IEC term dip. The category short duration varia-tions is used to refer to voltage dips and short interruptions. The term swell is introduced as an inverse to sag (dip). The category long duration variation has been added to deal with ANSI C84.1-1989 [B1] limits. The category noise has been added to deal with broad-band conducted phenomena. The category waveform dis-tortion is used as a container category for the IEC harmonics, interharmonics, and dc in ac networks phe-nomena as well as an additional phenomenon from IEEE Std 519-1992 [B13] called notching. Table 2 shows the categorization of electromagnetic phenomena used for the power quality community.
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Std 1159-1995IEEE RECOMMENDED PRACTICE FOR
10
The phenomena listed in table 1 can be described further by listing appropriate attributes. For steady-state phenomena, the following attributes can be used [B10]:
?
Amplitude ?
Frequency ?
Spectrum ?
Modulation ?
Source impedance ?
Notch depth ?Notch area
Table 1?Principal phenomena causing electromagnetic disturbances
as classiTed by the IEC Conducted low-frequency phenomena Harmonics, interharmonics
Signal systems (power line carrier)
V oltage ?uctuations
V oltage dips and interruptions
V oltage imbalance
Power-frequency variations
Induced low-frequency voltages
DC in ac networks
Radiated low-frequency phenomena Magnetic Telds
Electric Telds
Conducted high-frequency
phenomena Induced continuous wave voltages or currents
Unidirectional transients Oscillatory transients
Radiated high-frequency phenomena Magnetic Telds
Electric Telds
Electromagnetic Telds
Continuous waves
Transients
Electrostatic discharge phenomena
?Nuclear electromagnetic pulse ?
IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995 For non-steady state phenomena, other attributes may be required [B10]:
?Rate of rise
?Amplitude
?Duration
?Spectrum
?Frequency
?Rate of occurrence
?Energy potential
?Source impedance
Table 1 provides information regarding typical spectral content, duration, and magnitude where appropriate for each category of electromagnetic phenomena [B10], [B15], [B16]. The categories of table 2, when used with the attributes mentioned above, provide a means to clearly describe an electromagnetic disturbance. The categories and their descriptions are important in order to be able to classify measurement results and to describe electromagnetic phenomena that can cause power quality problems. The remainder of this clause will discuss each category in detail.
4.4 Detailed descriptions of phenomena
This subclause provides more detailed descriptions for each of the power quality variation categories pre-sented in table 2. These descriptions provide some history regarding the terms currently in use for each cate-gory. Typical causes of electromagnetic phenomena in each category are introduced, and are expanded in clause 8.
One of the main reasons for developing the different categories of electromagnetic phenomena is that there are different ways to solve power quality problems depending on the particular variation that is of concern. The different solutions available are discussed for each category. There are also different requirements for characterizing the phenomena using measurements. It is important to be able to classify events and electro-magnetic phenomena for analysis purposes. The measurement requirements for each category of electro-magnetic phenomenon are discussed.
4.4.1 Transients
The term transients has been used in the analysis of power system variations for a long time. Its name imme-diately conjures up the notion of an event that is undesirable but momentary in nature. The IEEE Std 100-1992 deTnition of transient re?ects this understanding. The primary deTnition uses the word rapid and talks of frequencies up to 3 MHz when deTning transient in the context of evaluating cable systems in substations. The notion of a damped oscillatory transient due to a RLC network is also mentioned. This is the type of phenomena that most power engineers think of when they hear the word transient.
Other deTnitions in IEEE Std 100-1992 are broader in scope and simply state that a transient is òthat part of the change in a variable that disappears during transition from one steady-state operating condition to another.ó Unfortunately, this deTnition could be used to describe just about anything unusual that happens on the power system.
Another word used in current IEEE standards that is synonymous with transient is surge. IEEE Std 100-1992 deTnes a surge as òa transient wave of current, potential, or power in an electric circuit.ó The IEEE C62 Col-lection [B14] uses the terms surge, switching surge, and transient to describe the same types of phenomena. For the purposes of this document, surge will not be used to describe transient electromagnetic phenomena. Since IEEE Std 100-1992 uses the term transient to deTne surge, this limitation should not cause con?icts. Broadly speaking, transients can be classiTed into two categories?impulsive and oscillatory. These terms re?ect the waveshape of a current or voltage transient.
11
IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR
12Table 2?Categories and typical characteristics of power system
electromagnetic phenomena
IEEE MONITORING ELECTRIC POWER QUALITY Std 1159-1995
13
4.4.1.1 Impulsive transient
An impulsive transient is a sudden, nonpower frequency change in the steady-state condition of voltage, cur-rent, or both, that is unidirectional in polarity (primarily either positive or negative).
Impulsive transients are normally characterized by their rise and decay times. These phenomena can also be described by their spectral content. For example, a 1.2/50 m s 2000 V impulsive transient rises to its peak value of 2000 V in 1.2 m s, and then decays to half its peak value in 50 m s [B14].
The most common cause of impulsive transients is lightning. Figure 1 illustrates a typical current impulsive transient caused by lightning.
Due to the high frequencies involved, impulsive transients are damped quickly by resistive circuit compo-nents and are not conducted far from their source. There can be signiTcant differences in the transient char-acteristic from one location within a building to another. Impulsive transients can excite power system resonance circuits and produce the following type of disturbance?oscillatory transients.
4.4.1.2 Oscillatory transient
An oscillatory transient consists of a voltage or current whose instantaneous value changes polarity rapidly.It is described by its spectral content (predominant frequency), duration, and magnitude. The spectral con-tent subclasses deTned in table 2 are high, medium, and low frequency. The frequency ranges for these clas-siTcations are chosen to coincide with common types of power system oscillatory transient phenomena.
As with impulsive transients, oscillatory transients can be measured with or without the fundamental fre-quency component included. When characterizing the transient, it is important to indicate the magnitude with and without the fundamental component.
Oscillatory transients with a primary frequency component greater than 500 kHz and a typical duration mea-sured in microseconds (or several cycles of the principal frequency) are considered high-frequency oscilla-tory transients. These transients are almost always due to some type of switching event. High-frequency
oscillatory transients are often the result of a local system response to an impulsive transient.
Figure 1?Lightning stroke current that can result in impulsive transients
on the power system
IEEE
Std 1159-1995IEEE RECOMMENDED PRACTICE FOR 14
Power electronic devices produce oscillatory voltage transients as a result of commutation and RLC snubber circuits. The transients can be in the high kilohertz range, last a few cycles of their fundamental frequency,and have repetition rates of several times per 60 Hz cycle (depending on the pulse number of the device) and magnitudes of 0.1 pu (less the 60 Hz component).
A transient with a primary frequency component between 5 and 500 kHz with duration measured in the tens of microseconds (or several cycles of the principal frequency) is termed a medium-frequency transient.
Back-to-back capacitor energization results in oscillatory transient currents in the tens of kilohertz. This phe-nomenon occurs when a capacitor bank is energized in close electrical proximity to a capacitor bank already in service. The energized bank sees the de-energized bank as a low impedance path (limited only by the inductance of the bus to which the banks are connected, typically small). Figure 2 illustrates the resulting current transient due to back-to-back capacitor switching. Cable switching results in oscillatory voltage tran-sients in the same frequency range. Medium-frequency transients can also be the result of a system response to an impulsive transient.
A transient with a primary frequency component less than 5 kHz, and a duration from 0.3 to 50 ms, is con-sidered a low-frequency transient.
This category of phenomena is frequently encountered on subtransmission and distribution systems and is caused by many types of events, primarily capacitor bank energization. The resulting voltage waveshape is very familiar to power system engineers and can be readily classiTed using the attributes discussed so far.Capacitor bank energization typically results in an oscillatory voltage transient with a primary frequency between 300 and 900 Hz. The transient has a peak magnitude that can approach 2.0 pu, but is typically 1.3D
1.5 pu lasting between 0.5 and 3 cycles, depending on the system damping (see Tgure 3).
Oscillatory transients with principal frequencies less than 300 Hz can also be found on the distribution sys-tem. These are generally associated with ferroresonance and transformer energization (see Tgure 4). Tran-sients involving series capacitors could also fall into this category. They occur when the system resonance results in magniTcation of low-frequency components in the transformer inrush current (second, third har-monic) or when unusual conditions result in ferroresonance.
IEEE Std C62.41-1991 [B14] describes surge waveforms deemed to represent the environment in which electrical equipment and surge protective devices will be expected to operate. Reference [B14] covers the origin of surge (transient) voltages, rate of occurrence and voltage levels in unprotected circuits, waveshapes
of representative surge voltages, energy, and source impedance.
Figure 2?Oscillatory transient caused by back-to-back capacitor switching
Q/CSG 中国南方电网有限责任公司企业标准 南方电网电能质量监测系统 验收技术规范 Q/CSG110004-2011 ICS 备案号: 目录 前言 (2) 1 范围 (3) 2 规范性引用文件 (3) 3 术语和定义 (3) 4 总则 (4) 5 工厂验收 (5) 6 现场验收 (8) 7 实用化验收 .............................................................. 10 附录 A 验收流程 ........................................................... 12 附录 B 验收文
档 ........................................................... 16 附录 C 工厂验收测试原始记录表 格 (80) 前言 为使中国南方电网有限责任公司电能质量监测系统验收工作具有专业性、规范性和可操作性,特制定本规范。 本规范由中国南方电网有限责任公司技术标准工作领导小组批准。 本规范由中国南方电网有限责任公司生产技术部提出、归口并解释。 本规范主编单位、参编单位、主要起草人和主要审查人: 主编单位:中国南方电网有限责任公司生产技术部 参编单位:广东电网公司生产技术部 广东电网公司深圳供电局 广东电网公司电力科学研究院 深圳领步科技公司 主要起草人:马健皇甫学真黄荣辉邱野梁洪浩刘文山钟聪曾强江健武赵继光李锐马明杨盛辉王海峰主要审查人:曾江韩民晓肖遥梅桂华刘军成董旭柱刘路彭波黄滔辛阔况华吴永华 1范围 本标准规定了电能质量监测系统工厂验收、现场验收及实用化验收的验收职责、验收组织与验收标准等内容。 本规范适用于中国南方电网有限责任公司(以下简称南方电网公司所辖交流 50Hz 电网范围内电能质量监测系统的验收工作。
电能质量管理制度 1 范围 本制度规定了***电能质量管理的职责、管理内容和办法、报告与记录。 本制度适用于***电能质量管理。 2 规范性引用文件 下列文件中的条款通过本标准的引用而构成为本标准的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本标准，然而，鼓励根据本标准达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本标准。 《电能质量电力系统频率允许偏差》（GB/T15945-1995） 《电能质量供电电压允许偏差》（GB1 2325-90） 《电能质量电压允许波动和闪变》（GB2 2326-90） 《电能质量三相电压允许不平衡度》（GB/T15543-1995） 《南方电网电厂辅助考核技术支持系统考核细则算法规范（试行）》，2009年11月 3 职责 3.1 厂生产副厂长或总工程师是电能质量技术监督工作的第一负责人，负责领导电能质量技术监督管理工作。 3.2 生产技术部为归口管理的职能部门，负责电能质量技术监督归口管理，制定实施细则，督促、检查电能质量技术监督工作。负责组织召开电能质量技术监督会议，总结交流技术监督工作，推广新技术，布置年度工作任务，定期发布电能质量情况。 3.3 设备部负责全厂调压设备的投运率、完好率，确保远动仪表遥传数据指示准确，对电压的监控设备不断进行完善、发现故障尽快消除，检查部对运行中的主要计定期进行抽查，保持在合格范围内。 3.4 发电部负责电能质量技术监督的管理工作，对全厂电能的质量负责。负责全厂电能质量监督过程中调压情况的统计、考核和管理工作。及时分析调压情况，做出报表。 4 管理内容与要求 4.1 电能监督范围 4.1.1 根据《南方电网电厂辅助考核技术支持系统考核细则算法规范（试行）》，调整#1-#3发电机无功负荷，使本厂220KV电压达到省调要求。 4.1.2 根据调度要求合理调整#1—#3发电机有功出力，保证系统频率在50HZ士0.5HZ范围，调压合格率在99.5%以上。 4.1.3 对220KV系统加强检查，合理调整运行方式，确保电压在合格范围内运行。 及时消除影响发电机系统正常运行的各类缺陷，保证各机组正常运行。强化我厂发、供电设备的可靠性管理，加强电气工作人员的安全教育和技术培训。 4.1.4 调压合格率以省调远动记录为依据，以小时为单位，日累计、月累加，调压合格率=当月本厂合格点数/当月全部点数×100%。 4.2 电能质量运行监督 4.2.1 发电部值班员负责调整#1--#3发电机无功负荷，使电压保持在合格范围内运行。 4.2.2 当发电机满足下列条件之一时，认为调压合格。 4.2.2.1 实际运行电压满足调度给定的电压调整曲线。 4.2.2.2 A VC功能投入省调。 4.2.2.3 实际运行电压虽然高于或低于调压给定值，但发电机运行出力或转子、定子电流满足规定。
《电网电能质量控制》 A 1. 电能质量的基本要求是什么？ 解答：为保证电能安全经济地输送、分配和使用，理想供电系统的运行应具有如下基本特性： （1）以单一恒定的电网标称频（50Hz 或60Hz ，我国采用50Hz ）、规定的若干电压等级（如配电系统一般为110kV ,35kV ,10kV ,380V/220V ）和以正弦函数波形变化的交流电向用户供电，并且这些运行参数不受用电负荷特性的影响。 （2）始终保持三相交流电压和负荷电流的平衡。用电设备汲取电能应当保证最大传输效率，即达到单位功率因数，同时各用电负荷之间互不干扰。 （3）电能的供应充足，即向电力用户的供电不中断，始终保证电气设备的正常工作与运转，并且每时每刻系统中的功率供需都是平衡的。 2. 简述长时间电压波动的内容及其特征 解答：长时间电压变动是指，在工频条件下电压均方根值偏离额定值，并且持续时间超过1min 的电压变动现象。 长时间电压变动可能时过电压也可能欠电压。 过电压 欠电压 持续中断 3. 什么是对称分量变换(120变换)？ 它适合哪种分析场合？ 120变换又称对称分量变换，它是一种把三相电流相量用正序、负序和零序对称分量来表示的变换。其变换公式为 (2-59) 式中， 互为共轭。 ???? ????????????=??????c b a 22211131i i i a a a a i i ,2321 ,232132232j e a j e a j j --==+-==-ππ
应用场合：是一种计算电力系统不平衡情况的工具，也可用于N相系统。 4. 改善电压偏差的措施有哪些？ 解答：（一）配置充足的无功功率电源 （二）系统调压手段 （1）电压偏差的调整方式：逆调压、顺调压、恒调压 （2）电压偏差的调整手段：用发电机调压、改变变压器变比调压、改变线路参数调压。 5. 什么是电力系统频率的一次调整和二次调整？ 解答：频率的一次调整是指利用发电机组的调速器，对于变动幅度小、变动周期短的频率偏差所做的调整。 频率的一次调整是指利用发电机组的调频器对于变动幅度大、变动周期长的频率偏差所做的调整。 6. 电压波动与闪变有哪些危害？ 1引起车间，工作室和生活居室等场所的照明灯光闪烁，使人的视觉易于疲劳甚至难以忍受而产生烦躁情绪，从而降低了工作效率和生活质量。 2 使得电视机画面亮度频繁变化以及垂直水平幅度摇晃。 3造成对直接与交流电源相连的电动机的转速不稳定，时而加速时而制动，由此可能影响产品质量，严重时危及设备本身安全运行。例如，对于造纸业，丝织业和精加工机床制品等行业，如果在生产运行时发生电压波动甚至会使产品报废等。 4对电压波动较为敏感的工艺过程或实验结果产生不良影响。例如使光电比色仪工作不正常，使化验结果出差错。5导致电子仪器和设备，计算机系统，自动控制生产线以及办公自动化设备等工作不正常，或受到损害。 5导致以电压相位角为控制指令的系统控制功能紊乱，致使电力电力换流器换向失败等。 顺便指出，波动性负荷除了会产生以上总结的闪变危害之外，由于自身的工作特点所决定，还会产生大量的谐波，并且由于其三相严重不对称带来的的
EPC项目质量管理要点 一、工程质量管理体系 我单位将在总包项目经理部下设工程部、技术部、质量管理部与材料设备部,全面负责该工程的质量管理工作。各分包单位应成立相应质量机构,协助总包搞好该分包单位的质量控制。在施工过程中,定期开展全面质量检查与质量问题分析会,各分包定期向总包提交质量月报表,掌握工程质量动态,应用科学的数理 统计分析方法,分析工程质量发展趋势,通过利用组织、技术、合同、经济的措施,达到“人、机、料、法、环”五大要素的有效控制,保证工程的整体质量。 二、工程质量控制管理机构 施工项目的质量控制管理机构作为工程质量创优的组织机构,其设置合理与否,将直接关系到整个质量保证体系能否顺利运转。 该机构就是由项目经理领导,项目总工负责,以质量管理部为主体,工程部、技术部、材料设备部参加的质量责任落实的质量管理体系,整个体系协调运作,从而使工程质量始终处于受控状态,形成项目经理为首,项目总工与项目副经理监控,职能部门执行监督,专业分包严格实施的网络化质量体系。 三、工程质量控制方法 根据本单位《质量保证手册》,结合工程的实际情况,编制施工组织设计及施工的专项施工方案,编写作业指导书与质量检验计划,编制项目《质量保证计划》,明确质量职责,确定项目创优计划,制定相应的质量制度。 四、对各分包的质量控制 1、质量控制管理方法 我单位将应用“全面质量管理”的原理,全员参与质量控制管理,对各专业分包单位施
工质量作全过程、全方位监控。 将各专业分包工程按“初步设计阶段、设计阶段、施工准备阶段、施工阶段、竣工验收阶段”划分,对各阶段制定相应的管理目标与流程图,在各阶段对分解目标按计划、执行、检查、处理四个过程进行循环操作(即PDCA循环)。分包施工过程中收集、整理质量记录的原始记录,应用数理统计方法,分析质量状况与发展趋势,有针对性地提出改进措施,对各工序施工质量作持续改进,通过工序施工质量控制整体质量。 2、总承包质量控制流程 总包质量控制流程图就是总包质量保证体系中的一个重要组成部分,就是规范总、分包之间质量管理行为的重要方式。 3、施工准备阶段的总包质量控制 (1)施工准备阶段总包质量控制的目标 ①对尚未进行招标的分包工程,择优选取分包单位。 ②对通过招标确定的分包单位指导与帮助其建立完善的质量管理体系与机构,督促分包单位配备的人员、设备、材料等满足质量技术要求,使各项技术文件、资料及施工现场正常交接,以便分包单位能迅速有效地开展工作。 (2)施工准备阶段的总包质量控制管理的措施: ①参与业主组织的分包招标,优选技术、管理先进的分包单位。 ②组织召开各分包单位参加的技术交底会,将有关设计文件、总包管理依据与程序、工艺要求、质量标准向分包作详细的书面交底。 ③组织有关单位对施工现场的主要坐标、轴线、标高、施工环境及相关技术资料进行交接,确保分包能及时、正确、有序地开展工作。 ④对分包单位的进场报告、开工报告进行审查,确保其质量保证体系、组织机构、人力
网络高等教育 本科生毕业论文（设计） 题目：电能质量问题与解决方法 学习中心： 层次：专科起点本科 专业： 年级：年春/秋季 学号： 学生： 指导教师： 完成日期：年月日
内容摘要 近年来,随着国民经济和电力系统的发展,电能供求关系的矛盾已逐步得到解决,但与此同时,有关电能质量的问题却日益引起人们的重视。电能质量如不能达到规定的要求,会给工、农业生产和日常生活带来种种问题,造成不可避免的损失。现代电力系统提出电能质量问题的概念是,任何出现的电压、电流以及频率偏移导致的用户设备损坏或运行不正常的电能问题,主要包括频率、电压、波形等内容。 本文对电能质量存在的问题及原因进行了分析，同时对解决电能质量所存在的问题的方法做了较为详细的介绍。 关键词：电能质量；电压偏差；频率偏差
目录 内容摘要 ........................................................................................................................... I 1 绪论 . (1) 1.1 课题的背景及意义 (1) 1.2 国内外发展现状 (2) 1.3 本文的主要内容 (5) 2 电能质量存在问题 (6) 2.1 电能质量问题分类及产生原因 (6) 2.2 电能质量问题产生的原因 (7) 2.2.1 电压偏差 (7) 2.2.2 频率偏差 (7) 2.2.3 谐波 (8) 2.2.4 电压波动与闪边 (9) 2.2.5 三相不平衡 (9) 2.3 电能质量影响指标 (10) 3 电能质量解决方法 (12) 3.1 传统方法 (12) 3.2 基于用户电力技术的解决方法 (12) 4 结论 (15) 参考文献 (16) 附录 (18)
电网电能质量控制B一、单选题 1.将参考坐标由旋转电机的定子侧转移到转子侧的坐标变换为（B）。 A.αβ变换 B.dq变换 C.傅里叶变换 D.小波变换 2.电能质量的基本要素是：电压合格、频率合格和（C） A.周期合格 B.电流合格 C.连续供电 D.三项平衡 3.电压波动与闪变的关系，以下叙述正确的是（B）。 A.电压波动是由闪变引起的，是一种电磁现象 B.闪变是电压波动的结果，是人对照度波动的主观视感反应 C.两者表述的意思相同 D.两者没有关系 4.单调谐滤波器有（A）种谐振频率。 A.一 B.两 C.三 D.四 5.电压暂降已经成为现代电力用户所面临的最重要的（A）干扰问题之一。 A.电能质量 B.用电质量 C.电压 D.电磁 6.长时间电压变动不包括（A）。 A.电压凹陷 B.过电压 C.欠电压 D.持续中断 7.具有故障自动恢复装置的断电为（A）。 A.短时间中断 B.长时间中断 C.电压中断 D.电流中断 8.GB/T15543-2008规定，电力系统公共连接点的正常电压不平衡度允许值为（C）。 A.4% B.3% C.2% D.1% 9.关于电能质量评估的复杂性的描述，错误的是（D）。 A.多个质量指标共同作用于一个系统，组合太多 B.电网节点多，电能质量问题具有传播性 C.不同电气设备在不同条件下对电压干扰的敏感度不同 D.电能质量测量仪表精度不够 10.根据IEEE定义电压电压暂降的电压下降幅度为标准电压的（A）。 A.90%-10% B.90%-1% C.85%-10% D.80%-1% 11.低压380V配电系统中电压谐波畸变率的允许值为（A）。 A.5% B.10% C.3% D.7% 12.在实际电力系统中，正序性谐波都有哪些（C）。
如何制定质量管理规定公司内部编号：（GOOD-TMMT-MMUT-UUPTY-UUYY-DTTI-
质量管理制度 一目的 为保证本公司质量管理制度的推行，并能提前发现异常、迅速处理改善，逐步提高产品质量，特制定本细则。 二质量管理的权责 （一）总经理室为本厂质量管理的领导部门。工艺部门为全厂质量管理的技术部门。 （二）本厂实行“部门内部控制，相关部门监督”的质量管理原则。 （三）各项质量标准与检验规范由工艺部门制订，由总经理室发布。 （四）部门内部质量控制措施由各部门制订、发布。报总经理室备案。 （五）总经理室制订对各部门的质量管理考核措施并组织落实。 （六）质量异议的最终裁决由总经理负责。 三工艺部门应制订下列质量文件： (一)原材料及外协加工配件质量标准及检验规范； (二)在制品质量标准及检验规范； (三)成品质量标准及检验规范； （四）工序操作标准； 四质量文件的修订 (一)各项质量文件若因①机械设备更新②技术改进③流程改善④市场需要⑤加工条件变更等因素变化，可以予以修订。 (二)工艺部门每年年底前至少重新校正一次，并参照以往质量管理实际情况会同有关部门检查各项标准及规范的合理性，进行修订。 五产品质量确认 下列情况要求质量确认：
(一)批量生产前的质量确认。 (二)客户要求质量确认。 (三)客户来图来样。 六质量管理作业实施要点 A 进料检验作业实施要点 (一)需用部门依照检验标准进行检验，并将进料厂商、品名、规格、数量等，填入检验记录表内。 (二)判定合格，即将进料加以标示"合格"，办理入库手续。 (三)判定不合格，即将进料加以标示"不合格"，填妥检验记录表及验收单内检验情况。并即将检验情况通知采购部门，由其依实际情况决定是否需要特采。 1.不需特采，即将进料加以标示"退货"，并于检验记录表、验收单内注明退货，由仓储人员及采购单位办理退货手续。 2.需要特采，由综合部经理批准，将进料加以标示"特采"，并于检验记录表、验收单内注明特采处理情况，办理入库或扣款等有关手续。 (四)检验时，如无法判定合格与否，则请工专业人员会同验收，会同验收者需在检验记录表内签章。 (五)检验时，抽样应随机化，并不得以个人或私人感情认为合用为由，予以判定合格与否。 (六)回馈进料检验情况，将供应商交货质量情况及检验处理情况登记于该供应商交货质量记录卡内，每月汇总制作供应商质量月报表报总经理室。 B 制程质量管理作业实施要点
电能质量管理出现的问题及解决 前言 电能质量即电力系统中电能的质量。理想的电能应该是完美对称的正弦波。一些因素会使波形偏离对称正弦，由此便产生了电能质量问题。一方面我们研究存在哪些影响因素会导致电能质量问题，一方面我们研究这些因素会导致哪些方面的问题，最后，我们要研究如何消除这些因素，从而最大程度上使电能接近正弦波。 定义 电能质量 (Power Quality)，从严格意思上讲，衡量电能质量的主要指标有电压、频率和波形。从普遍意义上讲是指优质供电，包括电压质量、电流质量、供电质量和用电质量。电能质量问题可以定义为：导致用电设备故障或不能正常工作的电压、电流或频率的偏差，其内容包括频率偏差、电压偏差、电压波动与闪变、三相不平衡、瞬时或暂态过电压、波形畸变(谐波)、电压暂降、中断、暂升以及供电连续性等。 [2] 影响因素 在现代电力系统中，电压暂降，暂升和短时中断，谐波产生的电压波形畸变;已成为最重要的电能质量问题。 电能质量监测改善前后对比图 产生电能质量问题的原理 无功功率的原理和解决方法： 电动机一类设备在磁场下工作，磁场在交流电下会不断储存和释放电能，但不会消耗电能，所以称为无功功率。无功功率虽然不会做功，但磁场储存能量的时候会需要流入电能，释放能量的时候又要流回去，这些来回流动的能量占用了线路、变压器、开关、发电机等设备的能力，不能充分发挥作用，而且还会增加线路损耗。
解决的办法是就近设置电场类设备也就是电容器，电场在交流电下也不断储存和释放能量，但正好和磁场储存和释放能量的时间错开，于是，磁场储存能量的时候就正好来自电场释放的能量，磁场释放的能量也正好存进电容器里去，无功功率就近互相提供，不再经过发电机、变压器、线路等系统设备了，这就是无功补偿原理。产生谐波的原理和不同谐波源谐波的解决方法： 如果正弦交流电压加在设备上，产生的电流却不是正弦交流电流，这样的设备就称为非线性阻抗设备，简称非线性设备。不是正弦波形的交流电就含有谐波成分，所以非线性设备也称为谐波源。 谐波会导致设备发热增加、产生附加负荷导致过载故障，引起线路干扰、还会因为共振导致设备中有谐振回路的部分损坏等等。 工业电网中主要的谐波源有三种类型： 三相桥式整流回路在每一相的正负波形上都会产生波形变化，一个周期里就有六个非正弦的波形，所以称为六脉波设备。六脉波设备的谐波很有规律，会产生六的倍数加减1次数的谐波，即5、7、11、13、17、19……次谐波，而且随着谐波次数升高谐波幅值会逐渐降低，所以通常只需要处理5、7、11、13次谐波。 这类设备包括有三相桥式整流器的所有设备、比如直流驱动器、变频器、软启动器，UPS电源等等，是目前工业用电设备中最常见的一类谐波源。 六脉波谐波源产生的谐波，次数稳定，可以用调谐技术滤除。 类似工业电弧炉这样的设备工作时，电流波形变化很频繁，会分解出次数和幅值不断变化的谐波。 这类谐波需要采用针对可变次数谐波进行滤除的技术，比如有源滤波技术。非线性的单相设备，比如带有单相整流环节的电子仪器等等，因为三相不对称原因会在零线上形成3次零序谐波。 零序3次谐波需要采用零序接法的滤除技术，比如四线制有源滤波，或者分相式无源滤波技术 改善措施 (1) 改善用电功率因数，使无功就地平衡。 (2) 合理选择供电半径. (3) 合理选择供电系统线路的导线截面。 (4) 合理配置变、配电设备，防止其过负荷运行。 (5) 适当选用调压措施，如串联补偿、变压器加装有载调压装置、安装同期调相机或静电电容器等。 供电电压超过允许偏差的原因有哪些? (1) 供电距离超过合理的供电半径。
全面质量管理的八大原则 ◆以顾客为中心 全面质量管理的第一个原则是以顾客为中心。在当今的经济活动中,任何一个组织都要依存于他们的顾客。组织或企业由于满足或超过了自己的顾客的需求,从而获得继续生存下去的动力和源泉。全面质量管理以顾客为中心,不断通过PDCA 循环进行持续的质量改进来满足顾客的需求。 ◆领导的作用 全面质量管理的第二大原则是领导的作用。一个企业从总经理层到员工层,都必须参与到质量 管理的活动中来,其中,最为重要的是企业的决策层必须对质量管理给予足够的重视。在我国的《质量管理法》中规定,质量部门必须由总经理直接领导。这样才能够使组织中的所有员工和资源都融入到全面质量管理之中。 ◆全员参与 全面质量管理的第三大原则就是强调全员参与。在70年代,日本的QC小组达到了70万个,而到目前为止我国已注册的QC小组已经超过了1500万个,这些QC 小组的活动每年给我国带来的收益超过2500亿人民币。因此,全员参与是全面质量管理思想的核心。 ◆过程方法 全面质量管理的第四大原则是过程方法,即必须将全面质量管理所涉及的相关资源和活动都作为一个过程来进行管理。PDCA循环实际上是用来研究一个过程,因此我们必须将注意力集中到产品生产和质量管理的全过程。 ◆系统管理
全面质量管理的第五个原则是系统管理。当我们进行一项质量改进活动的时候,首先需要制定、识别和确定目标,理解并统一管理一个有相互关联的过程所组成的体系。由于产品生产并不仅仅是生产部门的事情,因而需要我们组织所有部门都参与到这项活动中来,才能够最大限度地满足顾客的需求。 ◆持续改进 全面质量管理的第六个原则是持续改进。实际上,仅仅做对一件事情并不困难,而要把一件简单的事情成千上万次都做对,那才是不简单的。因此,持续改进是全面质量管理的核心思想,统计技术和计算机技术的应用正是为了更好地做好持续改进工作。 ◆以事实为基础 有效的决策是建立在对数据和信息进行合乎逻辑和直观的分析的基础上的,因此,作为迄今为止最为科学的质量管理,全面质量管理也必须以事实为依据,背离了事实基础那就没有任何意义,这就是全面质量管理的第七个原则。 ◆互利的供方关系 全面质量管理的第八大原则就是互利的供方关系,组织和供方之间保持互利关系,可增进两个组织创造价值的能力,从而为双方的进一步合作提供基础,谋取更大的共同利益。因此,全面质量管理实际上已经渗透到供应商的管理之中。
关于加强电能质量管理的几个问题林海雪 中国电力科学研究院，北京 改革开放以来，我国电力工业得到了快速的发展，目前已基本上摆脱了“供不应求”的局面。然而随着电网负荷结构的变化和大批新兴产业的崛起，电能质量的矛盾渐显突出，在许多情况下，制约了电力工业的发展，而电能质量管理方面的落后状况，必须引起电力企业和相关部门的高度重视。本文结合国内外现状和动向，就加强电能质量管理的几个问题谈些看法，以供参考。 提高对电能质量重要性的认识 电能质量关系到国民经济的总体效益 现代社会中，电能是一种最为广泛使用的能源，随着科学技术和国民经济的发展，对电能质量的要求越来越高。电能质量的指标若偏离正常水平过大，会给发电、输变电和用电带来不同程度的危害。 据统计，电网用电负荷中异步电动机占的比例最大。电网电压和频率的偏差、谐波、三相电压不平衡以及电压波动和闪变等，均会直接影响电机的转速、力矩和发热，从而影响生产工效和产品质量。 电网谐波含量增加，导致了电气设备寿命缩短，网损加大，系统发生谐波谐振的可能性增加，并联电容器不能正常运行，同时可能引发继电保护和自动装置的非故障性动作，导致仪表指示和电能计量不准以及计算机、通信受干扰等一系列问题[]。 随着计算机、电力电子和信息技术等高新产业的发展和普及，对电能质量提出了越来越高的要求。过去电力企业不甚关注的电能质量某些指标，例如电网中电压暂降（）和短时断电已成为一个突出的问题。一个计算中心失去电压就可能破坏几十个小时的数据处理结果或者损失几十万美元的产值。当今半导体芯片制造厂、自动化精加工生产线，对配电系统中电能质量的异常十分敏感，甚至几分之一秒的电压暂降就可能使生产停顿、设备损坏或出次品，在工厂内部造成混乱，而每次电压暂降可能造成百万美元级的损失，这些用户对不合格电能的容许度可以严格到～个[]。据美国电力科学研究院估计，当今和电能质量相关的问题，在美国每年造成的损失高达亿美元[]。美国电能质量方面一位知名专家下面一段话可以概括本节内容：“电能质量意味着经济问题，这一点特别重要，……电能质量问题会造成用户生产力下降，竞争力减弱，还影响到员工的就业，他们会影响到整个经济社会。”[]
江苏电网电能质量分析与改进对策 刘成民 摘要：本文总结了近年来江苏电网及系统中大容量非线性用户的谐波等电能质量问题的现状，就包括频率在内的的各电能质量问题进行了分析，并对新形势下的电能质量问题，提出防止对策。为江苏电网进一步提高电能质量提供了技术支撑。 关键词:电网, 电能质量, 对策 Power Quality Analysis And Improved Strategy for Jiangsu Power Network Abstract The present condition of power quality problems such as harmonic of nonlinear customer of large capacity in Jiangsu power network and system is concluded. Different power quality problems in Jiangsu Power Network are analyzed. According to new positions of power quality problems, some protection and strategy are presented, which provide technique support for increasing power quality in Jiangsu power network. Keywords power network，power quality，strategy 1现代电能质量概念 我国现有的电能质量方面的标准包括以下五个方面： （1）电力系统频率允许偏差；（2）供电电压允许偏差；（3）电压允许波动和闪变；（4）三相电压允许不平衡度；（5）公用电网谐波。 目前国内电能质量方面的工作主要集中在电压(幅值)、频率和谐波方面，而随着国民经济的发展和技术的进步，一方面电网中各种非线性负荷及用户不断增长，增加了影响电能质量的不利来源；另一方面各种复杂的、精密的、对电能质量敏感的用电设备使用也越来越多，对电能质量的要求更高，这两个方面的矛盾日益突出。为了确保有效控制电能质量，现实中不仅包括以上五个方面，更增添了新的内容：如电压凹陷、电压中断、电压瞬变、过电压、欠电压、间谐波等。从苏州、南京等地一批IT高新技术企业向供电公司提出供电电能质量和供电可靠性的要求，就鲜明的反映了电能质量的现实发展趋势。[1][2] 2江苏电网电能质量现状 2.1频率指标 2001年华东电网全网频率质量有所下降，江苏电网分摊的频率超出50±0.2HZ不合格时间为567.59秒，比2000年的267.7秒多299.89秒，合格率由2000年的99.999%下降到99.998%。不合格时间主要出现在6、7两个月，占全年不合格时间的68.2%。频率超出50±0.1HZ不合格时间为123337.05秒，比2000年的99203.06秒多24133.99秒，合格率由2000年的99.686%下降到99.608%。 2.2电压偏差指标 2001年江苏220千伏主网电压监控点2:00和9:00平均电压分别为230千伏和228千伏, 比2000年2:00和9:00平均电压230.8千伏和227.4千伏分别下降了0.8千伏和上升了0.6千伏。2001年全省220千伏电压监控点电压合格率为99.49%, 比2000年的99.4%上升0.09个百分点。 2.3电网谐波情况 （1）江苏500kV系统谐波数据
质量管理部门职责不清，不仅影响到工作效率，职责错位还容易导致人心不稳。 第一：质量管理部门管理要点、职责和岗位设置 1、质量管理组织内部管理要点： ·应有文件化的品管组织和隶属关系； ·品管内部的人员要有明确的职责分工（职位说明书）； ·文件化的品管权限－如原料，半成品，成品放行权等； ·有培训计划和培训执行记录； ·有内部奖惩制度，并与工资挂钩； ·要对产品质量数据的收集和分析，并与部门及责任人绩效挂钩。 2、质量管理部门的一般职责： ·进料检验－原料，辅料，包装物料等； ·过程监控－人、机、料、法、环； ·成品检验－人员，时机，依据，权限； ·监视测量装置的校准与管理； ·品质保证能力－质量体系的建立和推进； ·品质计划－产品标准，作业指导书，工艺文件，记录； ·客户投诉相关过程的管理－原因分析，就正措施，程序化； ·样品管理。 3、质量管理部门的主要岗位 ·原料/辅料/包装物料验收员（原料专员）； ·品管员－过程监控和监督，客户投诉的处理与跟踪； ·质检员－半成品、成品感官检验，检测样品取样； ·化验员－化验室检测； ·发货监装员； ·体系推进和考核； ·标准化管理员－官方文件的接收和处理，企业标准起草、备案，本部门第三层文件起草、修订，计量器具管理。 4、质量部门设置及分工是什么？ 质量检验工作：制程（生产过程）质量检验（IPQC），进料质量检验（IQC），装配质量检验，出货质量检验（OQC）；质量体系（QS），品质工程（QE），品质保证（QA），供应商质量管理（SQA）。 5、质量部工作的主要考核项目和指标：
·质量管理、质量检验制度是否完善； ·产品质量检验、生产过程控制是否完善、有效； ·计量检验器具是否定期校准，质量标准贯彻执行的情况； ·对关键生产工序的质量检验制度执行的情况； ·对原材料、外购件、成品的质量检验是否到位，是否有记录； ·质量管理体系运行是否全面、有效。 （2）主要指标： ·产品质量合格率； ·制成不良率； ·监测和测量仪器校准率； ·产品检验状态标识率； ·质量计划指标完成率； ·管理评审整改措施完成率； ·抽检不良率； ·纠正措施的有效率； ·原材料消耗下降率； ·质量成本指标完成率。 6、质量部门应达到的标准： ·质量管理的要求贯穿于企业经营管理的各项活动中，质量检验贯穿于产品生产经营的全过程，确保产品状态标识易于识别和可追溯； ·建立起规范的不合格品的鉴别、识别、记录、评审和处置办法； ·制订有效的预防措施，以消除潜在的不合格的原因，防止不合格的发生； ·制订有效的纠正措施标准，以消除不合格产生的原因以及顾客不满意的情况； ·建立并实施采购检验标准，以确保采购的产品满足规定的质量要求； ·质量记录完整、规范，内部审核、管理评审按计划执行，管理目标完成情况良好。 第二：质量管理部门各项工作的具体内容 1、进料管理： ·有明确的检验标准； ·验收流程要清晰； ·抽样的方法需正确； ·应定期对供应商进行现场评估；
电能质量现场测试规范 江西省电力公司 2012.5
前言 本规范的编制是针对江西省电力系统电能质量指标(公用电网谐波、三相电压不平衡度、电压波动及闪变)测试而制订。 一、范围 本规范适用于发电厂、变电站、用户端电能质量指标(公用电网谐波、三相电压不平衡度、电压波动及闪变)现场测试。 二、引用标准 GB/T14549-1993 《电能质量公用电网谐波》 GB/T15543-2008 《电能质量三相电压允许不平衡度》 GB/T 12326-2008 《电能质量电压波动和闪变》 电能质量综合测试分析仪技术说明书 三、测试前准备工作 3.1 人员要求 1）现场工作人员应身体健康、精神状态良好。 2）必须具备必要的电气知识、掌握本专业作业技能。 3）认真学习了本测试规范。 4）熟悉《电业安全工作规程》相关知识，并经考试合格。 5）有强烈的安全责任感。 3.2 工器具及材料 1）个人工具箱1套。 2）电能质量综合测试分析仪若干套（在有效期内）。 3）数字万用表1只（在有效期内）。 4）试验接线3套。 5）绝缘胶布1卷。 6）毛刷2把（1.5″）。 7）手电筒1个。
3.3 现场准备工作 1）开工前两天内，准备好本次测试所需电能质量综合测试分析仪、工器具、相关图纸，收集所测线路或机组的PT、CT变比，现场运行方式、供电主变容量、谐波源用户协议容量等相关技术资料。电能质量综合测试分析仪的电压、电流回路完好，工器具应试验合格，满足本次测试的要求，材料应齐全，图纸及资料应附合现场实际情况。 2）被测试单位根据现场工作时间和工作内容落实工作票，工作票应填写正确，并按《电业安全工作规程》相关部分执行。 3.4 安全提示 1）本规范所做测试不需拆动二次回路，测试中严禁拆动二次回路。 2）电流二次回路开路，易引起人员伤亡及设备损坏。 3）电压二次回路短路，易引起人员伤亡、设备损坏及保护误动。 3.5安全措施 1）做安全技术措施前应先检查附录A中的《现场安全技术措施》和实际接线及图纸是否一致，如发现不一致，及时向专业技术人员汇报，经确认无误后及时修改，修改正确后严格执行附录A中的《现场安全技术措施》。 2）检查在被测试设备相邻运行设备上确挂有红布幔。 3）必须正确使用工器具及仪器仪表。 4）严禁交、直流电压回路短路或接地。 5）严禁交流电流回路开路。 6）工作中应使用绝缘工具并戴手套。 7）在保护室内严禁使用无线通讯设备。 8）严禁电流回路开路或失去接地点，防止引起人员伤亡及设备损坏。 9）进入工作现场，必须正确使用劳保用品。 3.6 测试仪器的检查 1）检查测试仪器的电压输入方式是否与现场对应。若现场仅有三相三线，则应把电压输入线接成三相三线方式。在现场，尽可能找到三相四线的接线方式，以提高测试的准确度。
衡量电能质量的主要指标 随着国民经济的发展，科学技术的进步和生产过程的高度自动化，电网中各种非线性负荷及用户不断增长；各种复杂的、精密的，对电能质量敏感的用电设备越来越多。上述两方面的矛盾越来越突出，用户对电能质量的要求也更高，在这样的环境下，探讨电能质量领域的相关理论及其控制技术，分析我国电能质量管理和控制的发展趋势，具有很强的观实意义。 由于所处立场不同，关注或表征电能质量的角度不同，人们对电能质量的定义还未能达成完全的共识，但是对其主要技术指标都有较为一致的认识。 一、衡量电能质量的主要指标 (1) 电压偏差（voltagedeviation）：是电压下跌(电压跌落)和电压上升(电压隆起）的总称。 (2)频率偏差（friquencydeviation）：对频率质量的要求全网相同，不因用户而异，各国对于该项偏差标准都有相关规定。 (3) 电压三相不平衡（unbalance）：表现为电压的*大偏移与三相电压的平均值超过规定的标准。 (4) 谐波和间谐波（harmonics&inter-hamonics）：含有基波整数倍频率的正弦电压或电流称为谐波。含有基波非整数倍频率的正弦电压或电流称为间谐波，小于基波频率的分数次谐波也属于间谐波。 (5) 电压波动和闪变（fluctuation&flicker）：电压波动是指在包络线内的电压的有规则变动，或是幅值通常不超出0.9～1.1倍电压范围的一系列电压随机变化。闪变则是指电压波动对照明灯的视觉影响。 二、电能质量问题的产生 2.1电能质量问题的定义和分类 电能质量问题是众多单一类型电力系统干扰问题的总称，其实质是电压质量问题。电能质量问题按产生和持续时间可分为稳态电能质量问题和动态电能质量问题。 2.2电能质量问题产生原因分析 随着电力系统规模的不断扩大，电力系统电能质量问题的产生主要有以下几个原因。 2.2.1电力系统元件存在的非线性问题 电力系统元件的非线性问题主要包括：发电机产生的谐波；变压器产生的谐波；直流输电产生的谐波；输电线路（特别是超高压输电线路）对谐波的放大作
电网电能质量控制--本 -.综合题（70分） 1、简述电压波动的含义、引起电压波动的原因。 学生答案：电压均方根值一系列相对快速变动或连续改变的现象，其变化周期大于工频周期（20ms）。电压波动是指电网电压有效值（方均根值）的快速变动。电压波动值以用户公共供电点在时间上相邻的最大与最小电压方均根值之差对电网额定电压的百分值来表示；电压波动的频率用单位时间内电压波动（变动）的次数来表示。原因：（1）用电设备具有冲击负荷或波动负荷，如电弧炉、炼钢炉、轧钢机、电焊机、轨道交通、电气化铁路、以及短路试验负荷等。（2）系统发生短路故障，引起电网波动和闪变。（3）系统设备自动投切时产生操作波的影响，如备用电源自动投切、自动重合闸动作等。（4）系统遭受雷击引起的电网电压波动等。2.电压波动与闪变存在的影响电压闪变主要是表征人眼对灯闪主观感觉的参数。它一般是由开关动作或与系统的短路容量相比出现足够大的负荷变动引起的。 2、统一电能质量调节器的功能？ 3、什么是电力系统频率的一次调整和二次调整？ 学生答案：电力系统的负荷时刻都在变化，对系统实际负荷变化曲线的分析表明，系统负荷可以看做三种具有不同变化规律的变动负荷所组成：第一种是变化幅度很小，变化周期相对较短，一般是几秒就会变化的；第二种是变化幅度较大，变化周期较长，一般是几分钟；第三种是变化缓慢的持续变动负荷，引起负荷变化的原因主要是工厂的作息制度，人民的生活规律，气象条件的变化等。 第一种变化负荷引起的频率偏移将由发电机组的调速器进行调整，这种调整通常称为频率的一次调整。第二种变化负荷引起的频率变动仅靠调速器的作用往往不能将频率偏移限制在容许的范围之内，这是必须要有调频器参与频率调整，这种调整通常称为频率的二次调整。 当电力系统中负荷突然变大，那么频率将会相应降低，根据情况就会有一次二次调整。 4、电能质量的定义是什么？
质量管理10大要点和12个步骤（附质量口诀） “质量”一词与我们有着密切联系，质量就是企业的生命。品质是企业的名片，要想树立好的品牌，质量与品质必须有保障。高质量的产品是高质量的团队制造出来的，高质量的团队是管理出来的。因此，今天要分享的是质量管理10大要点和12个步骤： 01 10大要点 1.在第一时间把事情做对 有问题要在第一时间解决，不要等到工人做完了或等到最终检验时才发现，这样太晚了。 如果问题没有在第一时间加以解决，最终将导致产品不良，返工，客人退货，工厂的损失就会相当大，在每一个环节或每一道工序上实施和执行严格的进料检验和制程过程中的质量控制。这其中包括在生产线上每一种零部件和材料的加工处理。请注意，第三方检验公司不会发现许多错误，即使是他们发现了，这也太晚。 2.没亲眼看见结果就不要装样子 不要只是告诉你的员工做这个做那个，有些人会听从你的，但大多数人不会，你必须不断地用你的眼睛去看，去检查，去纠正和指导，不要只是告诉你的员工应该怎么样去做，你应该深入现场一线一遍一遍去看，去观察，去检查员工是否在按照你的要求操作， 你必须不断地指导和纠正你的员工，反反复复地去指导和纠正，直到正确的操作变成他们的条件反射，变成他们的工作习惯。这不是一朝一夕可以完成的。 3.不要以为有了模具和夹具就不会出现错误
如果你的模具或夹具是错的，那么生产出来的所有产品都是错的。要想办法将你的模具和夹具设计成工人只能按照你设计的唯一的，正确的方式放置待加工工件而没其他的选择。 让模具或夹具来控制工人的操作，不要指望让工人来控制模具或者夹具。因为，不管你告诉工人多少次应该怎么去做，有些人会听，但大多数人都不会听。把每天校准夹具的检查机器设备作为一项必须要做到的工作落实安排一个责任人，并且作为部门主管必须亲自检查的一项工作，并做好记录。 4.你怎么知道？ 在每天的管理工作中，不管你什么时候提出什么样的问题，你几乎总是会得到合适的回答，然而，实际上是没有人真正知道问题的真相。不要简单地把得到的回复作为正确的答案，你必须对员工进行持续的培训并亲眼见证他们的确是在正确地做事。必须进行内部审核，建立完善地内审制度以确保工人遵守工厂的标准作业流程。 在工厂内部的实验室测试必须是科学的，可靠的，并且，测试的记录必须能够根据测试日期和批号追究踪到生产线上的零件和产品，否则，该实验室的测试结果就跟样品测试一样了。如果他们不能反映大货生产的质量水平，就失去了测试的意义，大货生产的质量就失去了保障。 5.永远不要假设 不要想当然的回答：“我们以前从未有过任何问题，为什么要担心……..”。不要等到出现问题之后才采取行动，或认为问题不可能发生在你身上。要想办法去预防问题的可能发生。不要依靠“关系”（即你认识或熟悉的）来控制供应商的零部件和材料的质量以及品质的稳定性。 要严格实施与操作进料品质检验（即IQC），必要时，一些材料或零配件需要进行全检，有些材或零配件要按照规定的比例进行抽检，还有一些需要拿到实验室检测，实验室检测的要追究踪到具体的进货批次，批号，使用在具哪个合同单号上，如果测试结果不通过，就需要更换或停用那个特定批次的零配件或原材料，要坚持使“先进先出”（FIFO）的物料控制原则。 6.运用基本常识
一、单选题 1.电压源型变换器的英文缩写为（）。 A.UPQC B.VSC C.SVG D.SVC 2.根据对称分量法，下列哪项无法得到（）。 A.正序分量 B.基波分量 C.负序分量 D.零序分量 3.下列有关静止无功发生器的说法不正确的是（）。 A.英文缩写是SVC B.无功功率随电压的降低按一次方关系下降 C.采用PWM控制 D.具有更快的响应速度 4.基于数学变换方法分析电能质量问题的方法不包括哪一个（）。 A.傅里叶变换 B.方均根值计算方法 C.小波变换 D.矢量变换 5.架空线上发生的多数故障属于（）性质。 A.暂态 B.稳态 C.动态 D.临界态 6.为获取稳态情况下某电压波形中的谐波分量，最常用的变化为（） A.αβ变换 B.dq变换 C.傅里叶变换 D.小波变换 7.改善异步电动机启动方式不包括（）。 A.降压启动 B.串接变阻器启动 C.软启动 D.升压启动 8.总谐波畸变率的定义是（）。 A.总谐波有效值与基波有效值的百分比 B.总谐波有效值与额定值的百分比 C.基波有效值与额定值的百分比 D.基波有效值与总谐波有效值的百分比 9.基于瞬时无功功率理论的方法，在只检测（）时，可以完全无延时地得出检测结果。 A.无功电流 B.谐波电流 C.有功电流 D.基波电流 10.发电机的下列措施中有助于谐波抑制的是（）。 A.在三相发电机中，采用星形连接，线电动势中不出现3次及倍数次谐波电动势 B.凸极同步发电机采用适当的极靴宽度和不均匀的气隙长度，使气隙磁场的波形尽可能接近正弦分布 C.采用短距绕组，以消除某次谐波 D.以上三项都对 11.以下不属于电能质量基本概念的是（）。 A.电压质量 B.电流质量 C.供用电质量 D.输配电设备质量 12.对于高压电网中改变线路参数的方法中，用于减小线路电抗的方法常采用（）。 A.分裂导线 B.增加导线截面积 C.串联电抗器 D.并联电容器 13.改进型有源电力滤波器由有源滤波器、（）和检测与控制电路组成。 A.低通滤波器 B.C型低通滤波器 C.高通滤波器 D.C型高通滤波器 14.长时间电压中断的主要原因不包括（）。 A.永久性故障 B.瞬时性故障，重合闸拒动 C.线路故障检修 D.运行人员误操作 二、判断题 1.电力系统的电能质量始终是固定不变的（） 2.三相负荷不对称是系统三相不平衡的主要因素。（） 3.静止无功补偿装置是基于电力电子全控器件的装置。（） 4.频率质量监督和电压监测点的设置是电能质量技术监督的主要工作内容（） 5.整流电路会产生大量的谐波。（） 6.发生故障时，故障不仅会引起公共连接点幅值的降低，而且还会引起电压相位的跳变。（） 三、综合题 1.电能质量的定义是什么？ 2.统一电能质量调节器的功能? 3.什么是电力系统频率的一次调整和二次调整？ - 1 -