GB/T 7354-2018High-voltage test techniques -- Partial discharge measurements (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 7354-2003 "Partial Discharge Measurement". Compared with GB/T 7354-2003, the main changes are as follows.

--- Modified the definition of the term "digital partial discharge measuring instrument"; added the term "accumulated apparent charge" "number of partial discharge pulses"

Partial discharge mode";

--- Added a list of partial discharge measurement test procedures (for AC, DC);

---Modified the upper and lower limits of the broadband PD measurement system;

--- gives the calibrator - the condition that characterizes the unipolar step voltage amplitude U0 parameter;

--- In the performance test of the calibrator, an indirect measurement method of the step voltage rise time is given;

--- Added Appendix F partial discharge measuring instrument;

--- Added an assessment of the results of the partial discharge test during the DC voltage test in Appendix I.

This standard uses the redrafting method to modify the IEC 60270.2000 "High Voltage Test Technology Partial Discharge Measurement".

This standard has more structural adjustments than IEC 60270.2000. Appendix A lists this standard and IEC 60270.2000.

The chapter number is compared to the list.

The technical differences between this standard and IEC 60270.2000 and their reasons are as follows.

---About the normative reference documents, this standard has made technical adjustments to adapt to China's technical conditions, adjustments

The situation is reflected in Chapter 2, "Regulatory References", and the specific adjustments are as follows.

* Replace IEC 60060-1 with GB/T 16927.1-2011 modified to adopt international standards;

* Replace IEC 60060-2 with GB/T 16927.2-2013 modified to adopt international standards;

* Replace CISPR16-1.1993 with GB/T 6113.101 equivalent to the international standard;

--- In order to standardize test implementation and measurement, an enumeration of partial discharge measurement test procedures (for AC and DC) has been added;

--- In the performance test of the calibrator, in order to facilitate the operation and practical, an indirect measurement method of the step voltage rise time is given.

This standard also made the following editorial changes.

--- This standard incorporates amendments to IEC 60270.2000/Amd.1.2015, and the terms of these amendments have been adopted.

The vertical double line (||) of the outer side blank position is marked;

--- In the suppression of PD interference, the description of the single-point grounding method applied in China's power grid engineering has been added.

This standard was proposed by the China Electrical Equipment Industry Association.

This standard is under the jurisdiction of the National High Voltage Test Technology and Insulation Coordination Technical Committee (SAC/TC163).

This standard was drafted. Xi'an High Voltage Electric Apparatus Research Institute Co., Ltd., China Electric Power Research Institute Co., Ltd., China Metrology

Institute of Research, National High Voltage Electrical Apparatus Quality Supervision and Inspection Center, Machinery Industry Fifth (Xi'an) Metrology and Testing Center Station, Xi'an Xidian Switch Electric

Co., Ltd., Pinggao Group Co., Ltd., New Northeast Electric Group High Voltage Switchgear Co., Ltd., Shenyang Transformer Research Institute Co., Ltd.

Company, Beijing Beikai Electric Co., Ltd., Suzhou Huadian Electric Co., Ltd., Xi'an Xidian Power System Co., Ltd., Zhejiang

Guanchang Co., Ltd., Hunan Changgao High Voltage Switch Group Co., Ltd., Ningbo Kenli High Voltage Switch Technology Co., Ltd., Zhejiang Shitong Electric Manufacturing Co., Ltd.

Co., Ltd., Chongqing University, State Grid Anhui Electric Power Company Electric Power Research Institute, State Grid Shaanxi Electric Power Company Electric Power Research Institute,

Hebei Electric Power Company Electric Power Research Institute, State Grid Zhejiang Electric Power Company, State Grid Electric Power Research Institute Wuhan Nanrui Co., Ltd.

Division, State Grid Shanxi Electric Power Company Electric Power Research Institute, State Grid Shandong Electric Power Company Electric Power Research Institute, State Grid Hunan Electric Power Company

Electric Power Research Institute, State Grid Jiangsu Electric Power Company Electric Power Research Institute, Inner Mongolia Electric Power (Group) Co., Ltd., Yunnan Power Grid

Limited liability company Electric Power Research Institute, Shanghai Metrology and Testing Technology Research Institute, Hangzhou West Lake Electronics Research Institute, Kunming Electrical Apparatus Research Institute,

Yichang City, Hubei Province Metrology Testing Institute.

1 Scope

This standard defines the terminology of partial discharge and related measured parameters, specifies the test circuit used, the measurement circuit, and the general simulation.

And digital measurement methods, and give the calibration method and requirements for calibration instruments, test procedures, criteria for distinguishing between partial discharge and external interference.

This standard applies to electrical equipment, components or systems produced at AC voltage or DC voltage tests with a frequency of 400 Hz or less.

Raw partial discharge measurements.

The provisions of this standard can be used to draft technical conditions for partial discharge measurements of specific electrical equipment. This standard mainly involves pulse type (short duration

Time) Electrical measurements of partial discharges also give non-electrical measurement methods primarily used for partial discharge localization (see Appendix G).

The characteristic diagnosis of a particular power device can be digitized by a partial discharge signal (see Appendix F) and primarily for partial discharge

The non-electrical measurement method of the bit (see Appendix G) is completed.

This standard mainly describes the electrical measurement method of partial discharge during AC voltage test, and also mentions the special phenomenon that occurs during DC voltage test.

Special problem (see Chapter 4).

This standard terminology, definitions, basic test circuits and procedures are also generally applicable to tests conducted at other frequencies, but may require special

Special test methods and measurement system characteristics, these requirements are not considered in this standard.

Appendix B provides the requirements for calibrator performance testing as a requirement.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article.

Pieces. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 16927.1-2011 Part 1 . General definitions and test requirements (IEC 60060-1.2010,

MOD)

GB/T 16927.2-2013 High voltage test techniques - Part 2. Measurement systems (IEC 60060-2.2010, MOD)

GB/T 6113.101 Radio disturbance and immunity measuring equipment and measuring methods - Part 1-1. Radio disturbance and immunity

Measuring equipment measuring equipment (CISPR16-1-1..2010, IDT)

3 Terms and definitions

The following terms and definitions apply to this document.

3.1

Partial discharge partialdischarge; PD

Electrical insulation between conductors is only partially bridged electrical discharge. This discharge can occur near the conductor or not near the conductor.

Note 1. Partial discharge is generally caused by excessive concentration of local electric fields inside or on the insulating surface. Usually this discharge is characterized by a small duration

Pulse at 1µs. However, continuous forms may also occur, such as so-called pulseless discharges in gaseous media, usually measured by the standards described in this standard.

The method does not detect such discharges.

Note 2. "Corona" is a form of partial discharge that often occurs in a gaseous medium that is remote from a solid or liquid insulated conductor. "Corona" should not be used

A general term for all forms of partial discharge.

Note 3. Partial discharge is usually accompanied by phenomena such as sound, light, heat and chemical reaction. See Appendix G for more details.

3.2

Partial discharge pulse partialdischargepulse; PDPulse

When a partial discharge occurs in the test sample, the voltage or current pulse measured by the appropriate detection circuit in the test circuit is used. "current" or

The term "voltage" can be used in conjunction with "partial discharge" to indicate the type of detection.

Note. A partial discharge in the sample produces a current pulse. The detector in accordance with this standard will produce a current at its output with its input.

A pulsed charge proportional to the current or voltage signal.

3.3

Parameters related to partial discharge pulses

3.3.1

Apparent charge apparentcharge

Partial discharge For a specified test circuit, in a very short period of time, if the amount of charge injected into the sample ends causes the reading of the measuring instrument

The number corresponds to the reading caused by the partial discharge pulse.

Note. This amount of charge is the amount of apparent charge and is usually expressed in pico (pC).

3.3.2

Pulse repetition rate pulserepetitionrate

The ratio of the total number of partial discharge pulses recorded during the selected time interval to the time interval.

Note. Only pulses above the specified amplitude or in the specified amplitude range are actually considered.

3.3.3

Pulse repetition frequency pulserepetitionfrequency

For equally spaced pulses, N is the number of partial discharge pulses per second.

Note. The pulse repetition frequency N is related to the condition at the time of calibration.

3.3.4

The phase angle phii of the partial discharge pulse and the instantaneous ti phase angle phiiandtimetiofoccurrenceofaPDpulse

The relationship is shown in (1).

Phii=360(ti/T ) (1)

In the formula.

Phii---phase angle, generally expressed in degrees;

T---the period of the test voltage;

Ti - the time interval between the last positive zero crossing of the test voltage and the partial discharge pulse.

3.3.5

Average discharge current averagedischargecurrent

The derived amount is equal to the sum of the absolute values of the individual apparent charges qi within the selected reference time interval Tref divided by the time interval

[See equation (2)].

I=

Tref q1 q2

Qi( ) (2)

3.3.6

Discharge power dischargepower

The derived amount is equal to the average pulse power of the single apparent charge qi fed into the sample at the selected reference time interval Tref

[See equation (3)].

P=

Trefq1

U1 q2u2 qiui( ) (3)

In the formula.

U1, u2,, ui---the instantaneous value of the test voltage of the discharge instant ti corresponding to a single apparent charge qi, pay attention to the sign of each value

( /-).

The discharge power is generally expressed in watts (W).

3.3.7

Square rate quadraticrate

The derived amount is equal to the sum of the squares of the individual apparent charges qi over the selected reference time interval Tref divided by the time interval [see equation (4)].

D=

Trefq1

2 q22 qi2( ) (4)

The square rate is generally expressed in quadratic coulombs per second (C2/s).

3.3.8

Radio jammer radiodisturbancemeter

Use a quasi-peak measuring instrument of the B-band frequency consistent with GB/T 6113.101.

3.3.9

Radio interference voltage radiodisturbancevoltage

URDV

The amount of output, the radio jammer is used to indicate the reading of the local TV when the charge q, see 5.4.6 and see for more details.

Record E.

3.4

Repeated maximum partial discharge value largestrepeatedly-occurringPDmagnitude

The maximum magnitude recorded by the measurement system with the pulse sequence response specified in 5.2.3.

Repeated maximum partial discharge values are not applicable to DC voltage tests.

3.5

Specified partial discharge value specifiedpartialdischargemagnitude

The maximum value of the relevant partial discharge related parameters allowed under the specified conditions and test procedures under the specified voltage. For alternating current

In the pressure test, the specified value of the apparent charge q is the maximum partial discharge value that occurs repeatedly.

Note. Any partial discharge pulse parametric amplitude may vary randomly over a series of consecutive cycles and exhibit a tendency to increase or decrease during voltage action.

Therefore, the relevant technical committee should make corresponding provisions on the specified partial discharge amplitude, test procedures and test circuits and instruments.

3.6

Background noise level backgroundnoise

What was detected in the partial discharge test was not the signal produced by the sample.

Note. Background noise includes white noise, broadcast waves or other continuous or pulsed signals in the test system. See Appendix H for details.

3.7

Test voltage related to partial discharge pulse parameters

The test voltage associated with the partial discharge pulse parameters is defined in GB/T 16927.1-2011.

3.7.1

Partial discharge starting voltage partialdischargeinceptionvoltage

Ui

When the voltage applied to the sample is gradually increased from a lower value that does not observe the partial discharge to the first observation, the weight is generated in the sample.

The voltage at the time of renaturation partial discharge.

In fact, the starting voltage Ui is the lowest applied voltage when the partial discharge pulse parameter amplitude is equal to or exceeds a certain prescribed low value.

Note. For DC voltage tests, the determination of Ui requires special consideration, see Chapter 4.

3.7.2

Partial discharge extinguishing voltage partialdischargeextinctionvoltage

Ue

When the test voltage applied to the test sample gradually decreases from a certain observation to a higher value of the partial discharge pulse parameter until the sample stops appearing

The voltage at the time of repeated partial discharge. In fact, the extinction voltage Ue is when the selected partial discharge pulse parameter amplitude is equal to or less than a certain

The lowest applied voltage at a specified low value.

Note. For DC voltage tests, the determination of Ue requires special consideration, see Chapter 4.

3.7.3

Partial discharge test voltage partialdischargetestvoltage

The partial discharge pulse parameter of the sample is measured during the voltage application according to a prescribed voltage applied by a prescribed partial discharge test program.

Note. This voltage is the relative test voltage specified by the relevant product technical committee. In some cases, it can be determined by the user and the manufacturer.

3.8

Partial discharge measurement system partialdischargemeasuringsystem

The partial discharge measuring system includes a coupling device, a transmission system, and a measuring instrument.

3.9

Measuring system characteristics

The following definitions apply to the measurement system specified in Chapter 5.

3.9.1

Transmission impedance transferimpedance

Z(f)

When the input is a sinusoidal current, the ratio of the output voltage amplitude to a constant input current amplitude, Z(f) is a function of frequency f.

3.9.2

Lower limit frequency f1 and upper limit frequency f2 lowerandupperlimitfrequenciesf1andf2

The transmission impedance Z(f) is the frequency at which the passband peak drops by 6dB.

3.9.3

Center frequency fm and bandwidth deltaf midbandfrequencyfmandbandwidthdeltaf

The center frequency of all measurement systems is defined as equation (5).

Fm=

F1 f2

(5)

The bandwidth is defined as equation (6).

deltaf=f2-f1 (6)

3.9.4

Superposition error superpositionerror

When the input current pulse time interval is less than the duration of a single output response pulse, caused by the overlap of transient output impulse responses

of. Depending on the pulse repetition rate of the input pulse, the overlay error may accumulate or may be subtracted. In the actual loop, due to the pulse repetition rate

Machine characteristics, both cases may occur. However, since the measurement is based on the recurring maximum partial discharge value, usually only

Can detect additive errors with accumulation.

Note. The overlay error can be 100% or higher depending on the pulse repetition rate and the characteristics of the measurement system.

3.9.5

Pulse resolution time pulseresolutiontime

Tr

The shortest time interval between successive input pulses with very short duration, the same waveform and polarity, and equal charge, at this time

The amplitude of the impulse response in the interval is not more than 10% of the amplitude of the single pulse.

The pulse resolution time is generally inversely proportional to the bandwidth deltaf of the measurement system, and is also the ability of the measurement system to resolve continuous partial discharge phenomena.

Characterization.

Note. It is recommended to measure the pulse resolution time of the complete test circuit and measurement system, as the sample can also cause superimposed errors, such as wave reflections from the end of the cable.

The relevant technical committee should stipulate procedures for dealing with superimposed errors, especially allowing deviations to include positive or negative deviations.

3.9.6

Integral error integrationerror

When the upper limit frequency of the amplitude spectrum of the partial discharge current pulse is less than the following value, the error in the apparent charge measurement.

a) the upper limit frequency of the broadband measurement system; or

b) The center frequency of the narrowband measurement system.

See Figure 6.

Note. If a special electrical appliance is required, the relevant technical committee should stipulate stricter values of f1 and f2 to reduce the integral error.

3.10

Digital partial discharge measuring instrument digitalpartialdischargeinstruments

An instrument for data acquisition and evaluation of partial discharge signals.

Note. The A/D conversion of the partial discharge pulse captured from the sample terminal can be performed directly or an analog bandpass filter has been used in the apparent charge pulse.

Performed after the amplifier or an active integrator.

3.11

Scale factor scalefactor

Multiply the reading of the instrument to obtain the coefficient of the input value (3.5 of GB/T 16927.2-2013).

3.12

Cumulative apparent charge accumulatedapparentcharge

Qa

The sum of the apparent charges q of all individual pulses occurring during a specified time interval deltat that exceed a specified threshold level.

3.13

Partial discharge pulse number PDpulsecount

The total number of partial discharge pulses exceeding a predetermined threshold level within a prescribed time interval deltat.

3.14

Partial discharge mode PDpattern

The apparent charge q recorded during the specified time interval deltat is related to the partial discharge pulse phase angle phii and is displayed in a graph

Part discharge mode.

4 Test circuit and test procedure