CN107271751A - Alternating current-direct current Capacitor stack out-of-balance current method of testing - Google Patents
Alternating current-direct current Capacitor stack out-of-balance current method of testing Download PDFInfo
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- CN107271751A CN107271751A CN201710541861.4A CN201710541861A CN107271751A CN 107271751 A CN107271751 A CN 107271751A CN 201710541861 A CN201710541861 A CN 201710541861A CN 107271751 A CN107271751 A CN 107271751A
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- capacitor stack
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- balance current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0046—Arrangements for measuring currents or voltages or for indicating presence or sign thereof characterised by a specific application or detail not covered by any other subgroup of G01R19/00
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- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The present invention relates to a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing.It is characterized in, comprises the following steps：(1) capacitance first to every electric capacity on all bridge arms of Capacitor stack is measured, and is then stored obtained capacitance parameter, calculates the equivalent capacitance value of each bridge arm and the total impedance Z of bridge arm intermediate nodec；(2) apply low-voltage high-frequency AC signal at Capacitor stack two ends, unbalance voltage is measured at bridge arm intermediate node, the size of out-of-balance current value is finally calculated.The present invention proposes a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, by applying high frequency low voltage AC signal at Capacitor stack two ends, so as to measure out-of-balance current indirectly by unbalance voltage, this method efficiently reduces influence of the power frequency magnetic field to test result, measurement accuracy is greatly improved, and improves Security of test.
Description
Technical field
The present invention relates to a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing.
Background technology
Out-of-balance current test is the important indicator for evaluating filter condenser normal work and sensing capacitor failure.Tradition
Microampere meter as shown in Figure 2, is sealed in uneven TA loops, pressure regulator adds alternating voltage at capacitor two ends by method of testing
(hookup pressurization is generally below rated operational voltage), measures out-of-balance current, and the out-of-balance current value of measurement is converted
Respective value under to rated voltage.
The principle of traditional capacitor tower out-of-balance current test is although fairly simple, but according to the actual maintenance of current conversion station,
Commissioning experience, Capacitor stack bridge arm balance adjustment work is highly susceptible to the high frequency spoke for the high-energy that neighbouring wave filter group is produced
Blackberry lily is disturbed, line-frequency induction current interference, humiture influence and measures the influence such as length closed-loop path path of wiring.And with
Hz noise is most strong, and the induced-current amplitude probably caused in the range of 50Hz to 150Hz is maximum, and interference signal is concentrated mainly on
In the range of power frequency and odd number frequency multiplication, the interfering energy of other frequency ranges is smaller, causes the reading of microampere meter to produce very big error.
The content of the invention
It is an object of the invention to provide a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, can effectively it reduce
Influence of the power frequency magnetic field to test result, greatly improves measurement accuracy, and improve Security of test.
A kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, it is particular in that, comprises the following steps：
(1) capacitance first to every electric capacity on all bridge arms of Capacitor stack is measured, and then joins obtained capacitance
Number is stored, and calculates the equivalent capacitance value of each bridge arm and the total impedance Z of bridge arm intermediate nodec；
(2) apply low-voltage high-frequency AC signal at Capacitor stack two ends, unbalance voltage measured at bridge arm intermediate node,
Finally calculate the size of out-of-balance current value.
Wherein low-voltage high-frequency AC signal specifically refers to apply 1KHz alternating voltage at the two ends of Capacitor stack, and voltage has
Valid value 36V.
The size for wherein calculating out-of-balance current value is specifically referred to by the unbalance voltage and total impedance that measure under
Column count Formulas Io=Uoc/ZcCalculate out-of-balance current, wherein I0Represent out-of-balance current value, UocRepresent unbalance voltage.
The present invention proposes a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, by being applied at Capacitor stack two ends
Increase frequency low-voltage ac signal, so as to measure out-of-balance current indirectly by unbalance voltage, this method efficiently reduces work
Influence of the frequency magnetic field to test result, greatly improves measurement accuracy, and improve Security of test.
Brief description of the drawings
Accompanying drawing 1 is middle-and high-voltage capacitor tower elementary diagram of the present invention；
Accompanying drawing 2 is the conventional test methodologies schematic diagram in background of invention；
Accompanying drawing 3 is measuring principle schematic diagram of the invention；
Accompanying drawing 4 is measuring principle schematic diagram of the invention.
Embodiment
The invention provides a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, comprise the following steps：
(1) capacitance first to every electric capacity on all bridge arms of Capacitor stack is measured, and then joins obtained capacitance
Number is stored, and calculates the equivalent capacitance value of each bridge arm and the total impedance Z of bridge arm intermediate nodec；
(2) apply low-voltage high-frequency AC signal at Capacitor stack two ends, unbalance voltage measured at bridge arm intermediate node,
Finally calculate the size of out-of-balance current value.The size for wherein calculating out-of-balance current value specifically refers to injustice by measuring
Weighing apparatus voltage and total impedance pass through following calculating formula Io=Uoc/ZcCalculate out-of-balance current, wherein I0Out-of-balance current value is represented,
UocRepresent unbalance voltage.
Wherein low-voltage high-frequency AC signal specifically refers to apply 1KHz alternating voltage at the two ends of Capacitor stack, and voltage has
Valid value 36V.
Embodiment 1：
As shown in Figure 1, C1, C2, C3, C4 are four bridge arm equivalent electricity of Capacitor stack to high-voltage capacitor tower key wiring diagram
Container, wherein I is apply high-voltage capacitor tower through current under power-frequency voltage outside, and I1, I2, I3, I4 are respectively C1, C2, C3, C4
The electric current of branch road, IbphFor TA out-of-balance currents.
By neighbouring Hz noise than more serious during due to processing frequency voltage tester, therefore using giving Capacitor stack external high-frequency
The method of voltage, and effectively reduce influence of the interference to measurement, measuring principle block diagram by increasing shielding measure and signal filtering
As shown in Figure 3.
Apply 1KHz alternating voltage at the two ends of Capacitor stack, voltage effective value 36V, now each bridge arm capacitor bank
Total capacitive reactance is than that will reduce 20 times under power frequency, the out-of-balance current of same group capacitor tower is 20 times in the case of power frequency, and electric capacity
Small to general more than 100 ohm of the total impedance of bridge arm, and the impedance of digital microampere meter is basic more than 100 Europe, so with
Microampere meter goes measurement out-of-balance current error just very big.Therefore, we measure capacitor bridge using the method measured indirectly
Arm unbalance voltage, then calculates out-of-balance current according to Capacitor stack equiva lent impedance, to realize the uneven electricity of measurement indirectly
The purpose of stream.
Measurement out-of-balance current or unbalance voltage can embody the degree of unbalancedness of Capacitor stack, simply measure not
Balanced balanced current can intuitively reflect the uneven degree of capacitor tower.After high frequency voltage is applied to capacitor tower two ends, each bridge arm
The impedance of electric capacity is greatly reduced, and digital microampere meter to measurement the reason for internal resistance is big because having very big error, so can only enter
, can be according to active linear two in the case of known test frequency by measuring the capacitance of each bridge arm before row trim work
The analysis method of network theorem is held, by calculating the total impedance of capacitor tower intermediate node, as shown in Figure 4.
Electric capacity bridge arm intermediate node total impedance Zc：
Out-of-balance current I can be calculated by the unbalance voltage and total impedance that measureo=Uoc/Zc, so as to judge electric capacity
The whether exceeded alarm of the out-of-balance current scope of tower.
Claims (3)
1. a kind of alternating current-direct current Capacitor stack out-of-balance current method of testing, it is characterised in that comprise the following steps：
(1) capacitance first to every electric capacity on all bridge arms of Capacitor stack is measured, and then enters obtained capacitance parameter
Row storage, calculates the equivalent capacitance value of each bridge arm and the total impedance Z of bridge arm intermediate nodec；
(2) apply low-voltage high-frequency AC signal at Capacitor stack two ends, unbalance voltage is measured at bridge arm intermediate node, finally
Calculate the size of out-of-balance current value.
2. alternating current-direct current Capacitor stack out-of-balance current method of testing as claimed in claim 1, it is characterised in that：Its mesolow is high
Frequency AC signal specifically refers to apply 1KHz alternating voltage, voltage effective value 36V at the two ends of Capacitor stack.
3. alternating current-direct current Capacitor stack out-of-balance current method of testing as claimed in claim 1, it is characterised in that：Wherein calculate
The size of out-of-balance current value specifically refers to pass through following calculating formula I by the unbalance voltage and total impedance measuredo=Uoc/ZcMeter
Calculate out-of-balance current, wherein I0Represent out-of-balance current value, UocRepresent unbalance voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710541861.4A CN107271751A (en) | 2017-07-05 | 2017-07-05 | Alternating current-direct current Capacitor stack out-of-balance current method of testing |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710541861.4A CN107271751A (en) | 2017-07-05 | 2017-07-05 | Alternating current-direct current Capacitor stack out-of-balance current method of testing |
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| CN107271751A true CN107271751A (en) | 2017-10-20 |
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| CN201710541861.4A Pending CN107271751A (en) | 2017-07-05 | 2017-07-05 | Alternating current-direct current Capacitor stack out-of-balance current method of testing |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111562455A (en) * | 2020-04-22 | 2020-08-21 | 中国南方电网有限责任公司超高压输电公司大理局 | Capacitor bank fault positioning method and device for bridge difference unbalance protection |
| CN115201588A (en) * | 2022-07-18 | 2022-10-18 | 同济大学 | Detection system and method for unbalanced operation state of direct current capacitor bank |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2649360B2 (en) * | 1987-10-08 | 1997-09-03 | 株式会社日立製作所 | Parallel connection of gate turn-off thyristors |
| CN202351302U (en) * | 2011-11-25 | 2012-07-25 | 华北电网有限公司张家口供电公司 | Testing instrument for simulating unbalance current of serial compensating device |
-
2017
- 2017-07-05 CN CN201710541861.4A patent/CN107271751A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2649360B2 (en) * | 1987-10-08 | 1997-09-03 | 株式会社日立製作所 | Parallel connection of gate turn-off thyristors |
| CN202351302U (en) * | 2011-11-25 | 2012-07-25 | 华北电网有限公司张家口供电公司 | Testing instrument for simulating unbalance current of serial compensating device |
Non-Patent Citations (2)
| Title |
|---|
| 吴鹏: "《交直流滤波器及并联电容器装置运行及维护》", 30 April 2013 * |
| 李艳红等: "《电工电子技术及其应用》", 31 August 2013 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111562455A (en) * | 2020-04-22 | 2020-08-21 | 中国南方电网有限责任公司超高压输电公司大理局 | Capacitor bank fault positioning method and device for bridge difference unbalance protection |
| CN111562455B (en) * | 2020-04-22 | 2022-05-17 | 中国南方电网有限责任公司超高压输电公司大理局 | Capacitor bank fault positioning method and device for bridge difference unbalance protection |
| CN115201588A (en) * | 2022-07-18 | 2022-10-18 | 同济大学 | Detection system and method for unbalanced operation state of direct current capacitor bank |
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Application publication date: 20171020 |
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| RJ01 | Rejection of invention patent application after publication |