CN112564060A - AC filter unbalance protection method - Google Patents
AC filter unbalance protection method Download PDFInfo
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- CN112564060A CN112564060A CN202011278448.1A CN202011278448A CN112564060A CN 112564060 A CN112564060 A CN 112564060A CN 202011278448 A CN202011278448 A CN 202011278448A CN 112564060 A CN112564060 A CN 112564060A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Emergency Protection Circuit Devices (AREA)
- Testing Electric Properties And Detecting Electric Faults (AREA)
Abstract
The invention discloses an unbalance protection method of an alternating current filter, which comprises the following steps: theoretically calculating the reference current I of the unbalanced protection when the first capacitor element fails0(ii) a Real-time measurement of unbalance current I of whole capacitor bank in case of capacitor element fault2Data and calculating the present unbalance current I2With the reference value of the unbalance current I0A ratio; setting a constant value K, and setting the constant values K and I2、I0Comparing the ratios of (A) to (B); real-time measurement of tail current IT during capacitor element failure3Data and setting of unbalance protection input value IStarting upApplying the tail end current IT3With an unbalance protection input value IStarting upAnd (6) comparing. The invention is based on the unbalance protection principle of the ratio of the real-time unbalance current I2 to the unbalance current reference value I0, and is based on Siemens SIThe bidirectional counting principle of the C1 unbalanced protection of the MADYN D platform is simpler, the protection is more reliable, and the potential operation hazard of unbalanced protection miscounting and even misoperation is solved.
Description
Technical Field
The invention relates to the field of protection of alternating current filters, in particular to an unbalance protection method of an alternating current filter.
Background
The alternating current filter is a capacitor bank formed by combining a certain number of single capacitors in series and parallel. AC filter C1Unbalanced protection adopts C of SimADYN D platform of Siemens1The bidirectional counting principle of the unbalanced protection counts by detecting the step change of the unbalanced current of the capacitor bridge and adopts bidirectional counting logic. Unbalanced current T2And total current T3Sending the data to a protection device to obtain real-time deviation (delta IT)2/IT3) The protection device is provided with a branch counter and a total counter which reflect the fault condition of the internal elements of the capacitor through counting, thereby protecting the outlet action and removing the fault. The current principle has the following disadvantages:
1. the bidirectional counting principle has complex algorithm. IT (information technology) device2/IT3Analog quantity conversion based on SIMADYN D platform of Siemens is adopted, sampling is carried out, complicated integral conversion is carried out, and the sampling is stored in a Buffer moduleAnd (4) as an initial value of the imbalance ratio.
2. The bidirectional counting principle has poor anti-interference performance and often causes the phenomenon of miscounting.
Disclosure of Invention
The invention mainly solves the problems in the prior art and provides the unbalance protection method of the alternating current filter, which has the advantages of simple setting of the protection unbalance protection fixed value of the alternating current filter, simple program software logic, difficulty in causing error counting when being interfered and easiness in judging whether a capacitor really breaks down.
The invention is realized by the following technologies:
an unbalance protection method for an alternating current filter comprises the following steps:
s1, theoretically calculating out the unbalance protection reference current I when the first capacitor element is in fault according to the used alternating current filter0And is combined with0Curing on a protective device as a reference comparison value;
s2, measuring the unbalance current I of the whole capacitor bank in real time when the capacitor element is in fault2Data and calculating the present unbalance current I2With the reference value of the unbalance current I0A ratio;
s3, setting a constant value K, and comparing the constant value K with the constant value I2、I0When the unbalanced current I2With the reference value of the unbalance current I0When the ratio is larger than a fixed value K, the unbalanced protection acts; the calculation formula is as follows:
s4, measuring tail end current IT in real time when capacitor element is in fault3Data and setting of unbalance protection input value IStarting upApplying the tail end current IT3With an unbalance protection input value IStarting upIn contrast, the calculation formula is: IT (information technology) device3>IStarting up(ii) a When tail end current IT3Greater than the unbalance protection input value IStarting upWhen the protection is not balanced, the protection will be operated;
and S5, when S3 and S4 are simultaneously established, the unbalanced protection is started.
Further, the unbalanced protection action is divided into three sections, and fixed values of the three sections are set as follows:
when K is equal to n1The unbalance protection only sends out a warning signal, and in the event of an alarm, the filter or capacitor bank should still be able to continue to operate.
The first constant value detection action only signals a warning, i.e. in case of an alarm, the filter or capacitor bank should still be able to continue to operate. The first setting is chosen such that the voltage stress on the capacitive element subjected to the highest stress does not exceed the designed continuous nominal stress under any operating conditions, provided that the variation in frequency is within its continuous operating range.
When K is equal to n2The unbalanced protection immediately alarms and the packet is tripped after a two hour delay.
The second segment of fixed value detection action should alarm immediately and jump off the packet after a two hour delay. The second segment is chosen to have a constant value such that the voltage stress on the capacitive element subjected to the highest stress, under all operating conditions, meets the requirement of operating for two hours under nominal stress, assuming that the frequency varies within a normal continuous variation range.
When K is equal to n3The unbalanced protection immediately cuts out the packet. The third stage constant value detection action should immediately cut off the packet. The value of the constant is selected to avoid avalanche breakdown of the capacitive element. In addition, the voltage stress on the capacitor element that is subjected to the highest stress should not exceed twice the continuous rated stress that is designed assuming a frequency within the normal continuous variation range.
Wherein n is1<n2<n3。
The invention has the beneficial effects that:
1. based on real-time unbalanced current I2With the reference value of the unbalance current I0The ratio of (A) is more than that of C based on SIMADYN D platform of Siemens1The principle of the bidirectional counting principle of the unbalance protection is simpler, the protection is more reliable, and the potential operation hazard of the unbalance protection, such as miscounting and even misoperation, is solved;
2. the setting of the constant value is simple, and the protection principle only adopts unbalanced current I2The current value of the transformer solves the setting error caused by the transformation ratio of the current transformer in the process of setting the fixed value, and the protection is more reliable;
3. complex integral and analog conversion of current sampling of a SimADYN D platform are not needed, the hardware processing requirement of the protection device is reduced, the logic is optimized, and the load rate of a processor of the protection device is reduced;
4. the unbalanced current can correctly reflect the primary current value, and when unbalanced protection action occurs, the number of capacitor fault elements can be accurately judged according to the real-time unbalanced current ratio, so that accident analysis is facilitated, and the accident handling efficiency is improved.
5. Novel capacitor C1The unbalanced protection principle is suitable for protecting alternating current filters of various converter stations, can be applied and popularized in a plurality of domestic extra-high voltage direct current transmission projects, effectively solves the field practical problem, and has high practicability.
Drawings
FIG. 1 is a logic diagram of the present invention.
Detailed Description
In order to make the technical solution, object and advantages of the present invention more apparent, the present invention will be further explained with reference to the accompanying drawings and embodiments.
An unbalance protection method for an alternating current filter comprises the following steps:
s1, theoretically calculating out the unbalance protection reference current I when the first capacitor element is in fault according to the used alternating current filter0And is combined with0Curing on a protective device as a reference comparison value;
s2, measuring the unbalance current I of the whole capacitor bank in real time when the capacitor element is in fault2Data and calculating the present unbalance current I2With the reference value of the unbalance current I0A ratio;
s3, setting a constant value K, and comparing the constant value K with the constant value I2、I0When the unbalanced current I2With the reference value of the unbalance current I0Ratio greater thanWhen the value K is fixed, the unbalanced protection can act; the calculation formula is as follows:
wherein, according to the safe needs, set definite value K to three sections:
calculating the unbalanced current I of the capacitor element to reach 0-11 fault elements2Calculating the unbalance current I2With the reference value of the unbalance current I0The ratio, the number of faulty elements and the unbalance current are as follows:
| number of faulty elements | Unbalanced current value mA (first order value) | Ratio of |
| 0 | 0 | 0 |
| 1 | 24 | 1 |
| 2 | 51 | 2.125 |
| 3 | 81 | 3.375 |
| 4 | 115 | 4.79 |
| 5 | 152 | 6.33 |
| 6 | 194 | 8.08 |
| 7 | 241 | 10.04 |
| 8 | 295 | 12.3 |
| 9 | 357 | 14.875 |
| 10 | 429 | 17.875 |
| 11 | 514 | 21.42 |
The number of damaged capacitor elements is different, and the ratio is increased in a nonlinear way; therefore, in combination with the reliability factor, the three-stage unbalanced action ratio n is set1、n2、n3And when the value is larger than the corresponding segment constant value, protecting the action.
The first constant-value detection action only emitting a warning signal, i.e. in case of an alarm, the filter or capacitor bank should continue to operate. The first setting is chosen such that the voltage stress on the capacitive element subjected to the highest stress does not exceed the designed continuous nominal stress under any operating conditions, provided that the variation in frequency is within its continuous operating range. Thus, n is selected16, i.e. K6,
when 5 defective components are reached, the imbalance protection only sends out a warning signal, and in the event of an alarm, the filter or capacitor bank should still be able to continue operating.
The second segment of fixed value detection action should alarm immediately and jump off the packet after a two hour delay. The second segment is chosen to have a constant value such that the voltage stress on the capacitive element subjected to the highest stress, under all operating conditions, meets the requirement of operating for two hours under nominal stress, assuming that the frequency varies within a normal continuous variation range. Thus, n is selected210, i.e., K10,
when the number of damaged elements reaches 7, the unbalanced protection immediately alarms, and the grouping is skipped after a delay of two hours.
The third stage constant value detection action should immediately cut off the packet. The value of the constant is selected to avoid avalanche breakdown of the capacitive element. In addition, the voltage stress on the capacitor element that is subjected to the highest stress should not exceed twice the continuous rated stress that is designed assuming a frequency within the normal continuous variation range. Thus, n is selected317, i.e., K17,
when 10 damaged elements are reached, the unbalanced protection immediately cuts off the packet;
s4, measuring tail end current IT in real time when capacitor element is in fault3Data and setting of unbalance protection input value IStarting upApplying the tail end current IT3With an unbalance protection input value IStarting upIn contrast, the calculation formula is: IT (information technology) device3>IStarting up(ii) a When the tail end currentIT3Greater than the unbalance protection input value IStarting upWhen the protection is not balanced, the protection will be operated; according to safety standards and practical requirements, IStarting up＝0.1A；
And S5, when S3 and S4 are simultaneously established, the unbalanced protection is started.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention accordingly, and not to limit the protection scope of the present invention accordingly. All equivalent changes or modifications made in accordance with the spirit of the present disclosure are intended to be covered by the scope of the present disclosure.
Claims (2)
1. An AC filter imbalance protection method is characterized in that: the method comprises the following steps:
s1, theoretically calculating out the unbalance protection reference current I when the first capacitor element is in fault according to the used alternating current filter0And is combined with0Curing on a protective device as a reference comparison value;
s2, measuring the unbalance current I of the whole capacitor bank in real time when the capacitor element is in fault2Data and calculating the present unbalance current I2With the reference value of the unbalance current I0A ratio;
s3, setting a constant value K, and comparing the constant value K with the constant value I2、I0When the unbalanced current I2With the reference value of the unbalance current I0When the ratio is larger than a fixed value K, the unbalanced protection acts; the calculation formula is as follows:
s4, measuring tail end current IT in real time when capacitor element is in fault3Data and setting of unbalance protection input value IStarting upApplying the tail end current IT3With an unbalance protection input value IStarting upIn contrast, the calculation formula is: IT (information technology) device3>IStarting up(ii) a When tail end current IT3Greater than the unbalance protection input value IStarting upWhen the protection is not balanced, the protection will be operated;
and S5, when S3 and S4 are simultaneously established, the unbalanced protection is started.
2. An ac filter imbalance protection method as claimed in claim 1, wherein:
setting three fixed values of the unbalanced protection action;
when K is equal to n1When the unbalance protection only sends out a warning signal, the filter or capacitor group still continues to operate;
when K is equal to n2When the current is in the normal state, the unbalanced protection immediately alarms, and the grouping is skipped after the time delay of two hours;
when K is equal to n3When the packet is not received, the packet is immediately cut off by the unbalanced protection;
wherein n is1<n2<n3。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011278448.1A CN112564060A (en) | 2020-11-16 | 2020-11-16 | AC filter unbalance protection method |
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| CN202011278448.1A CN112564060A (en) | 2020-11-16 | 2020-11-16 | AC filter unbalance protection method |
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| CN112564060A true CN112564060A (en) | 2021-03-26 |
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| CN202011278448.1A Pending CN112564060A (en) | 2020-11-16 | 2020-11-16 | AC filter unbalance protection method |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108988367A (en) * | 2018-08-07 | 2018-12-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | A kind of H-type wiring capacitance device group degree of unbalancedness leveling method |
| 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 |
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2020
- 2020-11-16 CN CN202011278448.1A patent/CN112564060A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108988367A (en) * | 2018-08-07 | 2018-12-11 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | A kind of H-type wiring capacitance device group degree of unbalancedness leveling method |
| 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 |
Non-Patent Citations (1)
| Title |
|---|
| 何茂慧 等: "交流滤波器电容器不平衡保护动作逻辑分析", 《电工电气》 * |
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