CN113612190B - Method and system for executing reclosing of alternating current line based on safety margin index - Google Patents

Method and system for executing reclosing of alternating current line based on safety margin index Download PDF

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Publication number
CN113612190B
CN113612190B CN202110863038.1A CN202110863038A CN113612190B CN 113612190 B CN113612190 B CN 113612190B CN 202110863038 A CN202110863038 A CN 202110863038A CN 113612190 B CN113612190 B CN 113612190B
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time
preset
reclosing
safety margin
counter
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CN113612190A (en
Inventor
曹虹
王兴国
杜丁香
夏秋
谢民
俞斌
戴长春
章昊
汪伟
张骏
邵庆祝
于洋
孙辉
许旵鹏
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China Electric Power Research Institute Co Ltd CEPRI
State Grid Anhui Electric Power Co Ltd
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China Electric Power Research Institute Co Ltd CEPRI
State Grid Anhui Electric Power Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/06—Details with automatic reconnection
    • H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
    • 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
    • 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]

Abstract

The application discloses a method and a system for executing reclosing of an alternating current line based on safety margin indexes, and belongs to the technical field of relay protection. The method comprises the following steps: acquiring direct-current bipolar power, judging the safety margin of the direct-current system according to the acquired direct-current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct-current system by taking the disconnection time of the circuit breaker as 0 time, and acquiring a first judging result; determining an alternating current system safety margin index according to the first judging result; according to the safety margin index of the alternating current system, executing reclosing operation or non-reclosing operation of an alternating current line; the application can reduce the influence of secondary impact caused by superposition on a direct current system and avoid direct current blocking caused by continuous commutation failure.

Description

Method and system for executing reclosing of alternating current line based on safety margin index
Technical Field
The application relates to the technical field of relay protection, in particular to a method and a system for executing reclosing of an alternating current line based on safety margin indexes.
Background
With the rapid development of the ultra-high voltage direct current transmission technology, china enters an ultra-high voltage alternating current-direct current series-parallel power grid operation time, the characteristics of strong and weak alternating currents are increasingly outstanding, faults of an ultra-high voltage direct current near-area alternating current system can induce phase conversion failure of a direct current system, particularly permanent faults of an ultra-high voltage direct current near-area alternating current transmission line, if the faults coincide with the permanent faults, secondary impact is brought to the direct current system, continuous phase conversion failure is easy to cause, direct current blocking is caused, and once the direct current blocking fault occurs, huge power shortage occurs to a receiving-end power grid, and frequency and voltage stability of the power grid are affected. Therefore, the correct reclosing of the extra-high voltage direct current near-area alternating current line is important for the safe and stable operation of the whole power grid.
Reclosing technology is widely applied to alternating current transmission lines to coincide with transient faults and quickly restore power. However, the conventional reclosing technique does not distinguish between permanent faults and transient faults, and the circuit breaker is reclosed by a fixed delay, and then the faults are judged to determine whether to trip again, which is easy to cause adverse effects on an electric system.
Disclosure of Invention
In view of the above problems, the present application provides a method for executing reclosing of an ac line based on a safety margin indicator, including:
acquiring direct-current bipolar power, judging the safety margin of the direct-current system according to the acquired direct-current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct-current system by taking the disconnection time of the circuit breaker as 0 time, and acquiring a first judging result;
determining an alternating current system safety margin index according to the first judging result;
and executing reclosing operation or non-reclosing operation of the alternating current line according to the safety margin index of the alternating current system.
Optionally, the determining the safety margin of the direct current system includes:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 112, at the time T of determination, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Optionally, the determining the safety margin of the direct current system includes:
step 121, when the DC bipolar power is greater than the boundary transmission power P 0 When according toThe reclosing time T determines a first time period;
step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Optionally, the determining an ac system safety margin indicator according to the first determination result includes:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>Andis the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 To adjust the coefficient, 0<k 3 <1, when the safety margin of the direct current system is judged to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
Optionally, executing the reclosing operation or the non-reclosing operation of the ac line according to the safety margin index of the ac system includes:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m >U set When reclosing time T, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal;
wherein U is m Voltage magnitude relative to ground for fault; u (U) set And (5) providing safety margin indexes for the alternating current system.
The application also provides a system for executing reclosing of the alternating current line based on the safety margin index, which comprises:
the first judging unit is used for acquiring the direct-current bipolar power, judging the safety margin of the direct-current system according to the acquired direct-current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct-current system by taking the disconnection time of the circuit breaker as 0 time, and acquiring a first judging result;
the second judging unit is used for determining safety margin indexes of the alternating current system according to the first judging result;
and the execution unit is used for executing the reclosing operation or the non-reclosing operation of the alternating current line according to the safety margin index of the alternating current system.
Optionally, the first judgment result obtaining unit judges a safety margin of the direct current system, including:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 112, at the time T of determination, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Optionally, the first judgment result obtaining unit judges a safety margin of the direct current system, including:
step 121, when the DC bipolar power is greater than the boundary transmission power P 0 Determining a first time period according to the reclosing time T；
Step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Optionally, the ac system safety margin indicator determining unit determines an ac system safety margin indicator according to the first determination result, including:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>Andis the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 To adjust the coefficient, 0<k 3 <1, when the safety margin of the direct current system is judged to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
Optionally, the executing unit executes the reclosing operation or the non-reclosing operation of the ac line according to the safety margin index of the ac system, including:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m >U set And when the reclosing time T is over, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal.
According to the method and the system for executing reclosing of the alternating current line based on the safety margin index, the direct current bipolar power is obtained, the breaking moment of the circuit breaker is 0 moment, after a commutation failure signal of the direct current system is received, the safety margin of the direct current system is judged according to the obtained direct current bipolar power and the commutation failure signal, and a first judging result is obtained; determining an alternating current system safety margin index according to the first judging result; according to the safety margin index of the alternating current system, the reclosing operation or the non-reclosing operation of the alternating current line is executed, so that the influence of secondary impact caused by superposition on the direct current system can be reduced, and direct current blocking caused by continuous commutation failure is avoided.
Drawings
FIG. 1 is a flow chart of a method 100 for performing an AC line reclosing based on a safety margin indicator in accordance with an embodiment of the present application;
FIG. 2 is a logic diagram of reclosing in an embodiment of the method of the present application;
fig. 3 is a schematic diagram of a system 300 for performing ac line reclosing based on a safety margin indicator according to an embodiment of the present application.
Detailed Description
The exemplary embodiments of the present application will now be described with reference to the accompanying drawings, however, the present application may be embodied in many different forms and is not limited to the examples described herein, which are provided to fully and completely disclose the present application and fully convey the scope of the application to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the application. In the drawings, like elements/components are referred to by like reference numerals.
Unless otherwise indicated, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, it will be understood that terms defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
The application provides a method 100 for executing reclosing of an alternating current line based on safety margin indexes, as shown in fig. 1, comprising the following steps:
step 101, obtaining direct current bipolar power, taking the breaking moment of a breaker as 0 moment, judging the safety margin of the direct current system according to the obtained direct current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct current system, and obtaining a first judging result;
102, determining an alternating current system safety margin index according to the first judging result;
and step 103, executing the reclosing operation or the non-reclosing operation of the alternating current line according to the safety margin index of the alternating current system.
Wherein, the determining the safety margin of the direct current system includes:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 112, at the time T of determination, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Wherein, the determining the safety margin of the direct current system includes:
step 121, when the DC bipolar power is greater than the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 If any bridge commutation failure signal is received, the value of the updated counter is the current value of the counter and the preset step lengthAnd performing self-holding according to the preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Wherein, the determining the safety margin index of the ac system according to the first determination result includes:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>Andis the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 To adjust the coefficient, 0<k 3 <1, when the safety margin of the direct current system is judged to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
Wherein, according to the safety margin index of the ac system, the step of executing the reclosing operation or the non-reclosing operation of the ac line includes:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m >U set When reclosing time T, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal;
wherein U is m Voltage magnitude relative to ground for fault; u (U) set And (5) providing safety margin indexes for the alternating current system.
The application is further illustrated by the following examples:
wherein, the preset step length is 1, T 1 200ms, T 2 500ms, preset self-holding time of 200ms, T 3 200ms, T 4 400ms, wherein the first preset times are 3, and the second preset times are 2;
the specific implementation process comprises the following steps:
1. the method for judging the safety margin of the direct current system comprises the following steps:
and acquiring direct current transmission power and commutation failure signals, wherein the opening time of the circuit breaker is 0.
When the DC bipolar power is less than or equal to P 0 When the discrimination time T is within the first time period T-200 ms-T-500 ms, when any bridge commutation failure signal is receivedThe counter 1 is self-maintained for 200ms; time T at which counter 1 is updated date Forward 200ms to 400ms (i.e. T date -200ms～T date -400 ms) during which any bridge commutation failure signal is received, counter 2 and self-holding for 200ms; counter 2 receives any bridge commutation failure during the forward 200ms to 400ms, counter 3; if any of the above conditions is not satisfied, the counter is cleared to 0.T is reclosing time.
When the counter reaches 3, the system is determined to be in an unsafe state.
When the counter is less than 3, the system is determined to be in a safe state.
DC bipolar power>P 0 When judging that the time T is between T-200ms and T-500ms, when any bridge commutation failure signal is received, the counter counts 1 and self-maintains for 200ms; time T at which counter 1 is updated date Forward 200ms to 400ms (i.e. T date -200ms～T date -400 ms) receives any bridge commutation failure signal, counter 2, either of the above conditions is not met, counter 0 is cleared.
When the counter reaches 2, the system is determined to be in an unsafe state.
When the counter is less than 2, the system is determined to be in a safe state.
Wherein P is 0 Power is delivered to the boundary.
2. Making a determination of a safety margin of an ac system, comprising:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 The value range is 0.7-0.9 for the second margin coefficient,and->Current phasors for two sound phases, +.>And->Is the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 To adjust the coefficient, 0<k 3 <1, when the safety margin of the direct current system is judged to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 For the second preset coefficient threshold value, 0 < k 31 ＜k 32 ＜1。
3. And executing reclosing operation or non-reclosing operation of the alternating current line according to the safety margin index of the alternating current system.
In the application, as shown in fig. 2, the intelligent reclosing logic of the ac line executes different dc system safety margin judging logic according to the magnitude of the dc transmission power, adjusts the coefficient of the ac safety margin index according to the judging result, and finally judges whether to execute the reclosing command on the converter station side according to the adjusted coefficient. If the reclosing command is executed, executing the reclosing command when the reclosing time is T, simultaneously sending a reclosing allowing signal to the opposite side, and overlapping the opposite side after receiving the allowing signal. If the non-reclosing command is executed, the non-reclosing command is executed when the reclosing time T is over, and meanwhile, a reclosing locking signal is sent to the opposite side, and the opposite side is not reclosed after receiving the locking signal.
In the present application, the first preset number of times threshold is greater than the second preset number of times threshold.
The values of the parameters defined in the above embodiments are merely illustrative, and may be defined according to the need in actual operation, and are not limited to the values in the above examples. The application also provides a system 300 for executing reclosing of an alternating current line based on safety margin indexes, as shown in fig. 3, comprising:
the first determination result obtaining unit 301 is configured to obtain dc bipolar power, determine a safety margin of the dc system according to the obtained dc bipolar power and the commutation failure signal after receiving the commutation failure signal of the dc system with the opening time of the circuit breaker being 0, and obtain a first determination result.
Optionally, the first determination result obtaining unit 301 determines a safety margin of the dc system, including:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 112, at the time T of determination, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
Optionally, the first determination result obtaining unit 301 determines a safety margin of the dc system, including:
step 121, when the DC bipolar power is greater thanBoundary transport power P 0 Determining a first time period according to the reclosing time T;
step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The first preset time, the second preset time, the third preset time and the fourth preset time are respectively set.
An ac system safety margin indicator determining unit 302, configured to determine an ac system safety margin indicator according to the first determination result.
Optionally, the determining unit 302 for determining the safety margin indicator of the ac system according to the first determination result includes:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 Is the firstA margin coefficient k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>Andis the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 To adjust the coefficient, 0<k 3 <1, when the safety margin of the direct current system is judged to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
And the execution unit 303 is configured to execute an ac line reclosing operation or a non-reclosing operation according to the safety margin index of the ac system.
Optionally, the executing unit 303 executes an ac line reclosing operation or a non-reclosing operation according to the safety margin indicator of the ac system, including:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m >U set When reclosing time T, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal;
wherein U is m Voltage magnitude relative to ground for fault; u (U) set And (5) providing safety margin indexes for the alternating current system.
According to the application, different judging results of the safety margin of the direct current system and the safety margin of the alternating current system are combined, so that the reclosing scheme is optimized, the influence of secondary impact caused by superposition on the direct current system is reduced, and the direct current blocking caused by continuous commutation failure is avoided.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The scheme in the embodiment of the application can be realized by adopting various computer languages, such as object-oriented programming language Java, an transliteration script language JavaScript and the like.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (4)

1. A method of performing ac line reclosing based on a safety margin indicator, the method comprising:
acquiring direct-current bipolar power, judging the safety margin of the direct-current system according to the acquired direct-current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct-current system by taking the disconnection time of the circuit breaker as 0 time, and acquiring a first judging result;
determining an alternating current system safety margin index according to the first judging result;
according to the safety margin index of the alternating current system, executing reclosing operation or non-reclosing operation of an alternating current line;
wherein, the determining the safety margin of the direct current system includes:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 112, at the time of discriminationThe T is at the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The method comprises the steps of respectively obtaining a first preset time, a second preset time, a third preset time and a fourth preset time;
wherein, the determining the safety margin of the direct current system includes:
step 121, when the DC bipolar power is greater than the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The method comprises the steps of respectively obtaining a first preset time, a second preset time, a third preset time and a fourth preset time;
wherein, the determining the safety margin index of the ac system according to the first determination result includes:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>And->Is the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance; k (k) 3 For adjusting the coefficients, where 0 < k 3 < 1, when the safety margin of the DC system is determined to be in a safe state, k 3 For a first preset coefficient thresholdA value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
2. The method of claim 1, wherein performing an ac line reclosing operation or a no reclosing operation according to the ac system safety margin indicator comprises:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m ＞U set When reclosing time T, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal;
wherein U is m Voltage magnitude relative to ground for fault; u (U) set And (5) providing safety margin indexes for the alternating current system.
3. A system for performing ac line reclosing based on a safety margin indicator, the system comprising:
the first judging result obtaining unit is used for obtaining direct current bipolar power, taking the breaking moment of the breaker as 0 moment, judging the safety margin of the direct current system according to the obtained direct current bipolar power and the commutation failure signal after receiving the commutation failure signal of the direct current system, and obtaining a first judging result;
the alternating current system safety margin index determining unit is used for determining an alternating current system safety margin index according to the first judging result;
the execution unit is used for executing the reclosing operation or the non-reclosing operation of the alternating current line according to the safety margin index of the alternating current system;
the first judgment result obtaining unit is used for judging the safety margin of the direct current system and comprises the following steps:
step 111, when the DC bipolar power is less than or equal to the boundary transmission power P 0 At the time, determining the first according to the reclosing time TA period of time;
step 112, at the time T of determination, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 113, judging whether the value of the updated counter is greater than or equal to a first preset frequency threshold N1; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 114;
step 114, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 113;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The method comprises the steps of respectively obtaining a first preset time, a second preset time, a third preset time and a fourth preset time;
the first judgment result obtaining unit is used for judging the safety margin of the direct current system and comprises the following steps:
step 121, when the DC bipolar power is greater than the boundary transmission power P 0 Determining a first time period according to the reclosing time T;
step 122, at the distinguishing time T, in the first time period T-T 1 ～T-T 2 When the bridge commutation failure signal is received, updating the value of the counter to be the sum of the current value of the counter and a preset step length, and carrying out self-holding according to a preset self-holding time;
step 123, judging whether the updated counter value is greater than or equal to a second preset frequency threshold value N2; if yes, judging that the direct current system is in an unsafe state; otherwise, go to step 124;
step 124, according to the updated time T of the counter date Determining a second time period T date -T 3 ～T date -T 4 When any bridge commutation failure signal is received in the second time period, updating the value of the counter to be the sum of the current value of the calculator and a preset step length, and carrying out self-holding according to the preset self-holding time; and returns to step 123;
if the bridge commutation failure signal is not received, resetting the value of the counter, and judging that the direct current system is in a safe state;
wherein T is 1 、T 2 、T 3 And T 4 The method comprises the steps of respectively obtaining a first preset time, a second preset time, a third preset time and a fourth preset time;
the ac system safety margin indicator determining unit determines an ac system safety margin indicator according to the first determination result, including:
wherein U is set B is an alternating current side safety margin index 1 And b 0 Positive sequence and zero sequence susceptances, k, respectively, of unit length of ac line 1 For the first margin coefficient, k 2 As a second margin coefficient, the first margin coefficient,and->Current phasors for two sound phases, +.>And->Is the voltage phasor of two sound phases, Z m Mutual inductance of lines of unit length, Z l The self inductance of the unit length line is given, and l is the fault distance;k 3 for adjusting the coefficients, where 0 < k 3 < 1, when the safety margin of the DC system is determined to be in a safe state, k 3 A first preset coefficient threshold value; when the safety margin of the direct current system is judged to be in an unsafe state, k 3 And a second preset coefficient threshold value.
4. The system of claim 3, wherein the execution unit performs an ac line reclosing operation or a no reclosing operation according to the ac system safety margin indicator, comprising:
if U is m <U set When reclosing time T, determining to execute reclosing operation, simultaneously sending a reclosing permission signal to the opposite side, and executing reclosing after the opposite side receives the permission signal;
if U is m ＞U set When reclosing time T, determining to execute the non-reclosing operation, simultaneously sending a reclosing locking signal to the opposite side, and not executing reclosing after the opposite side receives the locking signal;
wherein U is m Voltage magnitude relative to ground for fault; u (U) set And (5) providing safety margin indexes for the alternating current system.
CN202110863038.1A 2021-07-29 2021-07-29 Method and system for executing reclosing of alternating current line based on safety margin index Active CN113612190B (en)

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CN110581564A (en) * 2019-08-12 2019-12-17 国家电网有限公司 Method and system for determining extra-high voltage direct current commutation failure accelerated protection strategy
CN112886532A (en) * 2021-01-15 2021-06-01 国网河南省电力公司电力科学研究院 Power transmission line self-adaptive reclosing method and system based on multi-source information

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CN105226620A (en) * 2015-10-28 2016-01-06 许继电气股份有限公司 A kind of implementation method of bipolar commutation failure protection
CN106532665A (en) * 2016-12-29 2017-03-22 国家电网公司 Commutation failure blocking method based on dynamic reclosing sequence
CN110137998A (en) * 2019-04-26 2019-08-16 南瑞集团有限公司 Pure electrical quantity commutation failure criterion method and system for safety and stability control device
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