Method and system for automatically identifying special operation mode of last outgoing line of AC line of converter station

Abstract

The application provides a method for automatically identifying special operation mode of the last outgoing line of an AC line of a converter station, which can effectively identify whether a special operation state of only one AC line of the converter station is in operation by comprehensively utilizing parameter information such as the operation state of the converter station, the position of a circuit breaker, the line voltage, the line current, the reclosing state and the like, and can remind the operation and maintenance personnel of the special working condition in real time, and automatically diagnose whether the current line reclosing operation state is correct, and if not, the line reclosing will be locked in time to avoid reclosing on a permanent fault in case of a fault, and a warning will be issued to remind the operation and maintenance personnel to change the reclosing state in time to avoid incorrect reclosing state in case of the special operation state of only one AC line of the converter station.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power system relay protection and automation, and more particularly to a method for real-time determination of the operation mode and reclosing state of the AC outgoing line of a converter station. BACKGROUND

[0002] For a DC power transmission system, one converter station operates in rectification state and the other station operates in inversion state. The operation state can be switched according to the needs and system operation mode. When the converter station operates in inversion state, the operation state of the AC outgoing line needs to be monitored in real time. The DC devices such as converter valves are the core devices of the converter station. In order to avoid damage to the DC devices, when only one AC line is operating, the reclosing of the line should be in the shutdown reclosing state, and when a fault occurs in the line, it should be directly tripped without reclosing.

[0003] At present, the comparative document 1 (D1 CN111884171B) discloses a single-phase fault line reclosing method and system for an AC / DC system. In order to solve the problem that the existing single-phase fault line reclosing method cannot distinguish between transient and permanent faults, resulting in low safety and stability of the AC / DC system. However, when the inversion station is only left with one AC outgoing line due to device tripping or change in operation mode, manual monitoring is mainly relied on, and there is a lack of automatic real-time monitoring technical means, which highly depends on the responsibility and technical level of personnel, and is easy to cause the running state to be not monitored, resulting in mismatch between the line reclosing state and the operation mode. When the only AC outgoing line fails, it is reclosed to a permanent fault, causing damage to DC devices such as converter valves, or when the last outgoing line is not in the shutdown reclosing state, any fault is not reclosed, resulting in loss of load and great safety hazards.

[0004] Therefore, there is an urgent need for a method for automatically identifying the operation state of the AC outgoing line of the converter station to remind the operation and maintenance personnel to exit the reclosing state in real time. SUMMARY

[0005] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a method for automatically identifying the special operation mode of the last outgoing line of the AC line of the converter station, which comprehensively utilizes the information of the circuit breaker position, line current, voltage, reclosing pressure plate state, etc., to automatically determine the operation state of the AC line of the inversion station in real time. When only one AC line is operating, an alarm information is sent in time to remind the operation and inspection personnel to change the reclosing state. After the present application is adopted, the reclosing state of the AC line can be ensured to match the operation mode of the AC line of the converter station, and the incorrect action of the relay protection device or the damage to the DC devices can be avoided.

[0006] The present application specifically adopts the following technical solutions:

[0007] In a first aspect, the present application discloses a method for automatically identifying the special operation mode of the last outgoing line of an AC line in a converter station, characterized in that the method comprises the following steps:

[0008] Step 1: judging whether the converter station is operating on the rectifier side or the inverter side, when judging that the station is operating on the rectifier side, no longer analyzing the operation state of the AC line, and when judging that the station is operating on the inverter side, entering the step of identifying the operation state of the AC line;

[0009] Step 2: obtaining the voltage U i , the current I i , and the breaker position D i of the AC line i in the station, and calculating the operation state Y i of each AC line in the station through logical operation;

[0010] Step 3: combining the operation state Y i of each AC outgoing line in the station to calculate the number Q of the currently operating AC lines;

[0011] Step 4: judging whether Q is 1, when Q≠1, displaying the number Q of the currently operating AC lines, and when Q=1, reading the reclosing state H i of the outgoing line of the AC line with Y i =1, and judging whether the AC line with Y i =1 is in the shutdown state according to H i .

[0012] Preferably, in Step 1, the current operation state G of the converter station is judged according to the trigger angle ɑ of the DC control system, when the trigger angle 90°<ɑ<180° exceeds 30 seconds, G=1, indicating that the station is operating in the inverter state, and when the trigger angle 0°<ɑ<90° exceeds 30 seconds, G=0, indicating that the station is operating in the rectifier state.

[0013] Preferably, in Step 2, the logical calculation formula for judging the operation state of the line i is: Y i =U i *D i +I i *D i , when Y i =1, it indicates that the line is in the live operation state, and when Y i =0, it indicates that the line is in the shutdown state.

[0014] Preferably, in Step 2, when the voltage U of any phase of the line is greater than 30V, U i =1, and when the voltages of all three phases satisfy U≤30V, U i =0.

[0015] Preferably, in Step 2, when the breaker of any phase of the line is in the closed position, D i=1, when all three phase circuit breakers are in the open position, D i =0.

[0016] Preferably, in step 2, the current I in any phase of the line is greater than 0.05I. n At that time, I i =1, when all three-phase currents satisfy I≤0.05I n At that time, I i =0;

[0017] Among them, I n The rated current for the secondary side is 1A or 5A.

[0018] Preferably, in step 3, the number of currently operating AC lines Q is calculated using the following formula:

[0019]

[0020] Where n is the total number of AC lines in the station, n≥1, and Q is the result of the numerical calculation.

[0021] Preferably, in step 4, when Q = 0, the inverter station is in a shutdown state;

[0022] When Q > 1, the line reclosing function is executed according to the setting sheet requirements.

[0023] Preferably, in step 4, when Q = 1, if H i =0 indicates that the reclosing is not in a stopped state. In this case, the reclosing of the line is blocked and an alarm signal is issued to remind that the current reclosing status of the line is incorrect.

[0024] If H i =1 indicates that the reclosing is in a stopped state, and a message is sent indicating that only one AC line is in operation in the station.

[0025] Secondly, the present invention also discloses a system for automatically identifying special operating modes of the last outgoing AC line of a converter station, comprising:

[0026] The converter station operation status judgment module, parameter acquisition module, first logic operation module, second logic operation module, first execution module, and second execution module are included.

[0027] The converter station operation status judgment module is used to determine whether the converter station is operating on the rectifier side or the inverter side;

[0028] The parameter acquisition module is used to obtain the voltage U of AC line i within the station. i Current I i Circuit breaker position D i state;

[0029] The first logic operation module is used to calculate the operating status Y of each AC line within the station.i ;

[0030] The second logic operation module, based on Y... i To calculate the current number of AC lines in operation, Q;

[0031] The first execution module is used to perform the following operations based on the value of Q: if Q≠1, then display the current number of AC lines in operation, Q; if Q=1, then read Y. i =1 outgoing reclosing status H i ;

[0032] The second execution module is used to determine H i The following operation is performed based on the value of H: If H i =0, then the reclosing of this line is blocked, and an alarm signal is issued to indicate that the current reclosing status of the line is incorrect; if H i =1, then a message is sent indicating that only one AC line is still in operation within the station.

[0033] Preferably, the first logic operation module calculates Y. i The formula is: Y i =U i *D i +I i *D i If Y i =1 indicates that the line is in a live operating state. If Y i =0 indicates that the line is out of service;

[0034] When the voltage of any phase of the line U > 30V, U i =1, when all three-phase voltages satisfy U≤30V, U i =0; When any phase circuit breaker of the line is in the closed position, D i =1, when all three phase circuit breakers are in the open position, D i =0; the current in any phase of the line I > 0.05I n At that time, I i =1, when all three-phase currents satisfy I≤0.05I n At that time, I i =0, I n The rated current for the secondary side is 1A or 5A.

[0035] Preferably, the second logic operation module calculates Y. i The formula is:

[0036]

[0037] Where n is the total number of AC lines in the station, n≥1, and Q is the result of the numerical calculation.

[0038] Compared with the prior art, the present application has the beneficial effects that:

[0039] The present application provides a method for automatically identifying the special operation mode of the last outgoing line of the AC line of the converter station, which can effectively identify whether the inverter station appears the special operation state of only one AC line running by comprehensively utilizing the parameters of the operation state of the converter station, the position of the circuit breaker, the line voltage, the line current, the reclosing state and the like, and real-time calculating the current number of AC outgoing lines in the station, and real-time reminding the operation and maintenance personnel to pay attention to the special working condition, and automatically diagnosing whether the reclosing operation state of the current line is correct, and if not, locking the line reclosing in time to avoid reclosing on permanent faults during faults, and issuing a warning to remind the operation and maintenance personnel to change the reclosing state in time to avoid the incorrect reclosing state under the special operation state of only one AC line running of the inverter station due to human reasons. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a flow chart of the method for automatically identifying the special operation mode of the last outgoing line of the AC line of the converter station of the present application.

[0041] Figure 2 is a primary wiring diagram of the AC line of the converter station of an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. The embodiments described in the present application are only a part of the embodiments of the present application, and cannot limit the protection scope of the present application. All other embodiments obtained by those skilled in the art without creative labor based on the spirit of the present application are within the protection scope of the present application.

[0043] As shown in Figure 1 , the method for automatically identifying the special operation mode of the last outgoing line of the AC line of the converter station of the present application specifically comprises the following steps:

[0044] Step 1: judging the current operation state G of the converter station according to the trigger angle a of the DC control system; if the trigger angle 90°<a<180° exceeds 30 seconds, G=1, indicating that it is running in the inverter state, then continue to calculate the AC line operation state; if the trigger angle 0°<a<90° exceeds 30 seconds, G=0, indicating that it is running in the rectifier state, then do not calculate the AC line operation state any more;

[0045] Step 2: if G=1, respectively collecting the voltage U i , the current I i and the circuit breaker position state D i, the running state Y of the AC line in the station is calculated by logical operation i ;

[0046] As shown in detail in Figure 2 , in step 2, the following logical judgment is used to determine whether the AC line i is in a running state or a shutdown state:

[0047] Wherein, when the voltage of any phase of the line U>30V, U i =1, and when the three-phase voltages all satisfy U≤30V, U i =0.

[0048] When the phase voltage of the line U>30V, ( A, B and C respectively) is used to determine whether the line has voltage; after the three-phase voltages are determined, an OR gate is taken, i.e. U i =U A +U B +U C , to prevent abnormality of a certain phase PT, or in the tripped state, when the voltage of any phase U>30V, U i is “1”, and when the three-phase voltages all satisfy U≤30V, U i is “0”.

[0049] When any phase breaker of the line is in the closed position, D i =1, and when the three-phase breakers are all in the open position, D i =0.

[0050] When the position of the phase breaker of the line is in the closed position, ( A, B and C respectively) is used to determine the position of the three-phase breaker of the line, and an OR gate is taken for the position of the three-phase breaker, i.e. D i =D A +D B +D C , to prevent abnormality of a certain phase breaker position relay, or in the tripped state, when any phase breaker is in the closed position, D i is “1”, and when the three-phase breakers are all in the open position, D i is “0”.

[0051] When the current of any phase of the line I>0.05I n , I i =1, and when the three-phase currents all satisfy I≤0.05I n , I i =0.

[0052] When the phase current of the line I>0.05I n (I n is the rated current at the secondary side, taking 1A or 5A), Phase, B phase and C phase) are used to determine whether the line has current; the three-phase currents are taken "or" gate, that is, I i = I A + I B + I C , to prevent a certain phase CT anomaly, or in the tripping state, when any phase current I>0.05I n , I i is "1", when the three-phase current meets I≤0.05I n , I i is "0";

[0053] The logic calculation formula for determining the line i operating state is: Y i = U i *D i + I i *D i , Y i =1, indicating that the line is in a live operating state, Y i =0, indicating that the line is in a shutdown state, wherein, step 2 uses Boolean operation, and the above U i , D i , I i , Y i are Boolean values;

[0054] According to the above formula, the operating state of each line can be calculated.

[0055] Step 3: Calculate the number of currently operating AC lines Q, the calculation formula is:

[0056]

[0057] Wherein, n is the total number of AC lines in the station, n≥1, and Q is the numerical operation result.

[0058] Step 4: Determine whether Q is 1, when Q≠1, display the first AC line operating number Q;

[0059] Specifically, when Q=0, it is the shutdown state of the inverter station; when Q>1, it is determined that two or more AC lines in the station are operating, and the AC line reclosing function can be executed according to the fixed value single requirement;

[0060] When Q=1, it is determined that only one AC line is operating in the station, then check the line number i of Y=1, and read the outgoing reclosing state H i of the AC line of Y i ​, check whether the line reclosing is in outage state.

[0061] Specifically, if H i = 0, Y i *H i = 0, it indicates that it is not in outage state, then the line reclosing is blocked, and an alarm signal is sent to remind the current line reclosing state is incorrect, and to remind the operation and maintenance personnel to timely put in the "outage reclosing pressure plate";

[0062] If H i = 1, Y i *H i = 1, it indicates that it is in outage state, then the reclosing command is not blocked, and only a message that there is only one AC line running in the station is reported, and only a "unique outgoing line running state" message is sent.

[0063] The application also discloses a system comprising a converter station running state judging module, a parameter collecting module, a first logic operation module, a second logic operation module, a first execution module and a second execution module; wherein

[0064] The converter station running state judging module is used for judging whether the converter station works on the rectifier side or the inverter side;

[0065] The parameter collecting module is used for acquiring the voltage U i , the current I i and the circuit breaker position D i state of the AC line i in the station;

[0066] The first logic operation module is used for calculating the running state Y i of each AC line in the station.

[0067] The formula of Y i is Y i = U i *D i + I i *D i , if Y i = 1, it indicates that the line is in live running state, and if Y i = 0, it indicates that the line is in outage state.

[0068] When the voltage of any phase of the line is greater than 30V, U i = 1, and when the three-phase voltages all satisfy U≤30V, U i = 0.

[0069] When the phase voltage U of the line is greater than 30V, ( A, B and C respectively) are used for judging whether the line has voltage; after the three-phase voltages are judged, an "or" gate is taken, namely Ui =U A +U B +U C To prevent a single phase PT from malfunctioning, or in a tripped state, when any phase voltage U > 30V, U i The value is "1" when all three-phase voltages satisfy U≤30V. i =0;

[0070] When any phase circuit breaker of the line is in the closed position, D i =1, when all three phase circuit breakers are in the open position, D i =0;

[0071] When the phase-by-phase circuit breaker of the line is in the closed position ( Phases (representing phases A, B, and C respectively) are used to determine the position of the three-phase circuit breakers. The position of the three-phase circuit breakers is determined by an OR gate, i.e., D. i =D A +D B +D C To prevent a faulty position relay of a certain phase circuit breaker, or in a tripped state, when any phase circuit breaker is in the closed position, D i The value is "1" when all three phase circuit breakers are in the open position. i =0;

[0072] The current in any phase of the line is I > 0.05I. n At that time, I i =1, when all three-phase currents satisfy I≤0.05I n At that time, I i =0;

[0073] When the line phase current I > 0.05I n Time (I) n (This refers to the rated current on the secondary side, either 1A or 5A.) ( The three phases (A, B, and C) are used to determine if there is current in the line; after determining the three-phase current, an OR gate is used, i.e., I0. i =I A +I B +I C To prevent abnormality of a single phase CT, or in a tripped state, when the current I in any phase is greater than 0.05I... n At that time, I i The value is "1" when all three-phase currents satisfy I ≤ 0.05I. n At that time, I i =0;

[0074] The logical calculation formula for determining the operating status of line i is: Y i =Ui D i I i D i Y i = 1, indicating that the line is in a live state, Y i = 0, indicating that the line is in a shutdown state, wherein, step 2 uses Boolean operation, and the above U i D i I i Y i are Boolean values;

[0075] The second logic operation module is used to combine the running states Y i of the AC outgoing lines in the station to calculate the number Q of the currently running AC lines, and the calculation formula is:

[0076]

[0077] wherein, n is the total number of the AC lines in the station, n≥1, and Q is a numerical operation result.

[0078] The first execution module is used to perform corresponding operations according to the value of Q, if Q≠1, the number Q of the currently running AC lines is displayed; if Q=1, the reclosing state (H i ) of the outgoing line of the AC line with Y i =1 is read.

[0079] The second execution module is used to perform corresponding operations according to the value of H i , if H i =0, Y i *H i =0, the reclosing of the line is locked, and an alarm signal is sent to remind that the reclosing state of the current line is incorrect; if H i =1, Y i *H i =1, a message that there is only one AC line running in the station is reported.

[0080] The application has the beneficial effect that, compared with the prior art, the application provides a method for automatically identifying the special operation mode of the last outgoing line of the AC line of the converter station, the number of the AC line operation in the station is calculated by comprehensively using the rectification / inversion state of the converter station, the position of the AC line circuit breaker, the current, the voltage and other information, and is displayed in real time, when the calculation result is 1, whether the line outage reclosing state is put into is checked, when it is not put into, real-time alarm can be given, and the line reclosing is locked. Therefore, the method provided by the application can judge the number of the AC line operation in the station in real time, when only one AC outgoing line is left, whether the line works in the outage reclosing state can be automatically judged, when the state is not correct, the reclosing can be automatically locked, which is simple and reliable, and does not need to rely on manual judgment of the AC line operation state.

[0081] The applicant has made detailed description and explanation of the embodiments of the application in combination with the drawings of the specification, but those skilled in the art should understand that the above embodiments are only preferred embodiments of the application, and the detailed description is only to help the reader better understand the spirit of the application, and is not a limitation on the protection scope of the application, on the contrary, any improvement or modification based on the spirit of the application should fall within the protection scope of the application.

Claims

1. A method for automatically identifying a special operation mode of an outgoing line of an alternating current line of a converter station, characterized in that, Comprising: Step 1: Determine whether the converter station is working on the rectifier side or the inverter side, when it is determined to be the rectifier side, no longer analyze the AC line operation state, when it is determined to be the inverter side, then enter the identification of AC line operation state link; Step 2: Get the voltage U of the station internal AC line i i , the current I i , the breaker position D i , and the state of the station internal AC line i i ; Step 3: Combine the running state Y of each AC outgoing line in the station i , calculate the number of currently running AC lines Q; Step 4: Determine whether Q is 1, when Q≠1, display the first AC line operation quantity Q; When Q = 1, read Y i = 1 of the AC line reclosing state H i , and according to H i determine whether the reclosing of the AC line with Y i = 1 is in the outage state.

2. The method of claim 1, wherein, In step 1, according to the trigger angle α of the DC control system, the running state G of the current converter station is determined; if the trigger angle 90°< α <180° exceeds 30 seconds, G=1, indicating that it is running in the inverter state; if the trigger angle 0°< α <90° exceeds 30 seconds, G=0, indicating that it is running in the rectifier state.

3. The method of claim 1, wherein, In step 2, the logical calculation formula for judging the line i operating state is: Y i = U i * D i + I i * D i If Y i = 1, it indicates that the line is in a live operating state, and if Y i = 0, it indicates that the line is in a shutdown state.

4. The method of claim 3, wherein, In step 2, when any phase voltage U>30V, U i =1, when all three phase voltages satisfy U≤30V, U i =0.

5. The method of claim 3, wherein, In Step 2, D = 1 when any phase breaker on the line is in the closed position i and D = 0 when all three phase breakers are in the open position. i and D = 0 when all three phase breakers are in the open position.

6. The method of claim 3, wherein, In step 2, the current in any phase of the line I > 0.05I. n At that time, I i =1, when all three-phase currents satisfy I≤0.05I n At that time, I i =0; where I n is the secondary side rated current, taken as 1 A or 5 A.

7. The method of claim 1, wherein, In step 3, the number of currently operating AC lines Q is calculated, and the calculation formula is: Wherein, n is the total number of AC lines in the station, n≥1, and Q is the numerical operation result.

8. The method of claim 1, wherein, In step 4, when Q=0, it is the inverter station shutdown state; When Q>1, the line reclosing function is executed according to the requirement of the fixed value single.

9. The method of claim 1, wherein, In Step 4, when Q = 1, if H i = 0, it indicates that the reclosing of the line is not in the outage state, then the reclosing of the line is blocked, and an alarm signal is sent to remind that the current reclosing state of the line is incorrect. If H i = 1, it means that the reclosing is in the stop state, and a message that there is only one AC line operating in the station is reported.

10. A system for automatically identifying a special operating mode of the last outgoing line of an AC line of a converter station, the method according to any one of claims 1 to 9 being implemented, characterized in that, Comprising: A converter station running state judgment module, a parameter acquisition module, a first logic operation module, a second logic operation module, a first execution module and a second execution module; Wherein The converter station running state judgment module is used to determine whether the converter station is working on the rectifier side or the inverter side; The parameter acquisition module is configured to acquire voltage U of the AC line i in the station i , current I i , breaker position D i state; The first logic operation module is used for calculating the operation state Y of each AC line in the station i ; The second logic operation module calculates the number of current active transmission lines Q according to Y i ; The first execution module is configured to perform the following operation according to the value of Q: if Q≠1, display the number Q of the first AC line operation; if Q=1, read the out-of-line reclosing state H of the AC line with Y i =1 i ; The second executing module is used for executing the following operation according to the value of H i If H i =0, the circuit reclosing is locked and an alarm signal is sent to remind that the current circuit reclosing state is incorrect; if H i =1, a message that only one AC circuit is running in the station is reported.

11. The system of claim 10, wherein: The first logic operation module calculates Y i The formula is: Y i = U i * D i + I i * D i If Y i = 1, it indicates that the line is in a live operating state, and if Y i = 0, it indicates that the line is in a shutdown state; Wherein, when any phase voltage of the line is greater than 30V, U i =1, when all three phase voltages are less than or equal to 30V, U i =0; when any phase circuit breaker of the line is in the closed position, D i =1, when all three phase circuit breakers are in the open position, D i =0. Line any phase current I > 0.05I n When I i = 1, when three-phase current all meet I ≤ 0.05I n When I i = 0, I n is the secondary side rated current, take 1A or 5A.

12. The system of claim 10, wherein: The second logic operation module calculates Y i The formula is: Wherein, n is the total number of AC lines in the station, n≥1, and Q is the numerical operation result.

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