Control and protection system anti-locking method based on abnormal identification of measured data of converter station

Abstract

The invention discloses a control and protection system anti-locking method based on converter station measurement data abnormity identification. The method comprises the following steps: measuring direct current measurement point data in at least two sets of control and protection systems in a converter station in real time; in the judgment period, when the variable quantity of all measurement data of any direct-current measurement point of the on-duty control and protection system is greater than a first fixed value, if the variable quantity of the measurement data of any direct-current measurement point of the standby control and protection system or the variable quantity of the measurement data of a direct-current measurement point adjacent to the any direct-current measurement point in the on-duty control and protection system is less than or equal to the first fixed value, the standby control and protection system is started; if so, determining that the DC measurement is abnormal; otherwise, according to the measurement value of the adjacent direct current measurement point, the measurement value of the standby control and protection system and the indirect calculation value, whether direct current measurement abnormity occurs is identified; and shielding or normally executing a direct-current protection action signal of the control and protection system associated with the direct-current measuring point according to an identification result. According to the invention, the risk of direct current locking caused by abnormal direct current measurement of a single measuring point is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage direct current transmission control and protection, and more specifically, relates to an anti-locking method for a control and protection system based on abnormal identification of converter station measurement data. Background Art

[0002] DC measuring equipment provides primary electrical quantity signals for the control and protection system of the UHV converter station. The reliability of its measurement data is directly related to the safe operation of the DC transmission system. Due to the particularity of DC transmission, DC measuring equipment such as pure optical transformers, zero flux CT, DC voltage dividers, and electronic transformers are commonly used in DC transmission projects. Different from the principles of traditional electromagnetic transformers, the reliability of DC measuring equipment is still insufficient.

[0003] Although the DC control protection system and the DC measurement secondary circuit adopt a redundant configuration method, which can effectively reduce the problem of malfunction or refusal of the control protection system caused by faults in the DC measurement secondary circuit, when the DC measurement primary equipment is affected by external interference, DC measurement data abnormalities still occur from time to time, and malfunction of the control protection system is still difficult to avoid. During the operation of the converter station, there have been many converter transformer lockout events caused by abnormal measurements of a single measurement device. The main reason for the DC lockout caused by the existing DC measurement equipment is that the DC control protection system cannot effectively identify abnormal DC measurement data.

[0004] Due to the persistent problem of converter station lockout caused by DC measurement equipment in recent years, researchers at home and abroad have conducted a lot of research on the problem of DC measurement equipment failure. However, the research mainly focuses on the status assessment, fault diagnosis and reliability improvement of DC measurement equipment such as optical CT. There is currently no method in the existing technology to fundamentally eliminate the problem of DC measurement equipment failure. Some research involves the DC lockout problem caused by abnormal DC measurement data in converter stations, but it mainly focuses on the analysis of the causes of DC lockout accidents. The existing technology lacks a method to accurately identify abnormal DC measurement data from the perspective of DC control protection. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a control and protection system anti-locking method based on converter station measurement data abnormality identification. Based on the difference between the measurement abnormality of a single DC measuring point and the electrical characteristic quantity after the actual converter station failure, measurement data abnormality identification is realized by comparing and verifying the information of different measuring points, thereby avoiding the risk of DC locking caused by DC measurement abnormality at a single measuring point in the DC transmission project.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention provides a control and protection system anti-locking method based on abnormal identification of converter station measurement data, comprising:

[0008] Real-time measurement of the DC measurement point data in at least two control and protection systems in the converter station, wherein the control and protection systems include a duty control and protection system and at least one standby control and protection system;

[0009] During the determination period, when the changes in all the measurement data of any DC measurement point of the on-duty control and protection system are greater than the first fixed value, if the changes in the measurement data of any DC measurement point of the standby control and protection system or the changes in the measurement data of the DC measurement point adjacent to the any DC measurement point in the on-duty control and protection system is less than or equal to the first fixed value, it is determined that a DC measurement abnormality has occurred, the DC protection action signal of the control and protection system associated with the any DC measurement point is shielded and the determination is terminated; if the changes in the measurement data of the DC measurement points adjacent to the any DC measurement point in the on-duty control and protection system are greater than the first fixed value, whether a DC measurement abnormality has occurred is identified based on the measurement values ​​of the DC measurement points adjacent to the any DC measurement point in the on-duty control and protection system, the measurement values ​​of any DC measurement points in the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measurement points;

[0010] According to the abnormal identification result of DC measurement, the DC protection action signal of the control and protection system associated with the DC measurement point is shielded or executed normally;

[0011] During the determination period, when the changes in all measurement data of any DC measurement point of the on-duty control and protection system are not greater than the first set value, continue to measure the data of each DC measurement point in the DC field of the converter station.

[0012] Preferably, the determination period is set to be N≥2 consecutive sampling points.

[0013] Preferably, the first set value ε1 is smaller than the starting set value of the DC protection action criterion in which the DC measuring point participates.

[0014] Preferably, the first constant ε1 is set to be 0.05-0.08 pu.

[0015] Preferably, the calculation formulas for adjacent DC measuring points and indirect calculation values ​​are determined according to the primary main wiring diagram of the DC field of the converter station.

[0016] Preferably, the indirect calculation value takes into account the main circuit topology and the randomness of the fault location, and is calculated based on the measurement values ​​of adjacent measurement points.

[0017] Preferably, identifying whether a DC measurement abnormality occurs according to the measurement value of a DC measurement point adjacent to any DC measurement point in the on-duty control and protection system, the measurement value of any DC measurement point in the standby control and protection system, and the indirect calculation value based on the adjacent DC measurement point specifically includes:

[0018] Calculate the average value V_MEAN of the measured value V_MEAS1 of the adjacent DC measuring point in the on-duty control and protection system, the measured value V_MEAS2 of the DC measuring point in the standby control and protection system, and the indirect calculated value V_CALC of the adjacent measuring point. If the absolute value of the difference between the average value V_MEAN and the measured value V_MEAS of the DC measuring point in the on-duty control and protection system exceeds the second fixed value ε2, it is determined that a DC measurement abnormality has occurred; otherwise, it is determined that no DC measurement abnormality has occurred.

[0019] Preferably, the second constant ε2 is set to be 0.05-0.08 pu.

[0020] Preferably, shielding or normally executing the DC protection action signal of the control and protection system associated with the DC measurement point according to the DC measurement abnormality identification result specifically includes:

[0021] If the DC measurement abnormality identification result determines that a DC measurement abnormality has occurred, the DC protection action signal associated with the DC measurement point in the DC control and protection system is shielded. Otherwise, the DC protection signal associated with the DC measurement point in the DC control and protection system is executed normally.

[0022] A second aspect of the present invention provides a control and protection system based on abnormal identification of converter station measurement data, using the control and protection system anti-locking method based on abnormal identification of converter station measurement data to perform exit discrimination of protection action signals, including:

[0023] The DC data detection module is used to measure the data of each DC measuring point in the DC field of the converter station in real time and detect whether the change of the DC measuring point measurement data exceeds the set threshold within the judgment period. The DC measuring point data includes two sets of data of the on-duty control and protection system and the standby control and protection system;

[0024] The adjacent measuring point determination module is used to determine whether the measurement data change of the adjacent DC measuring points exceeds the set threshold;

[0025] An indirect calculation and determination module is used to identify whether a DC measurement abnormality occurs based on the measurement values ​​of the adjacent DC measurement points of the on-duty control and protection system, the measurement values ​​of the DC measurement points of the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measurement points;

[0026] The protection action shielding module is used to shield or normally execute the DC protection action signal associated with the DC measurement point according to the DC measurement abnormality identification result.

[0027] Compared with the prior art, the beneficial effects of the present invention include at least:

[0028] (1) The present invention identifies abnormalities in the data of a single DC measurement point based on the multi-source measurement information of the DC control and protection system. The implementation method is simple and reliable, and can directly avoid the risk of DC false locking caused by a single DC measurement abnormality.

[0029] (2) The present invention adopts multiple criteria to determine whether a DC measurement abnormality occurs, accurately identifies abnormal DC measurement data, has higher stability and reliability, and effectively avoids misjudgment of the control and protection system during commutation failure at the converter station and restart of the DC line.

[0030] (3) The present invention uses indirect calculation values ​​calculated in a variety of ways to identify abnormalities, taking into account the randomness of the main circuit topology and the fault location, thereby improving the utilization rate of measurement data and effectively identifying abnormal DC measurement data. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the anti-locking method of the control and protection system based on abnormal identification of converter station measurement data in the present invention;

[0032] Figure 2 It is a data anomaly identification method used in the anti-lockout logic block diagram of the DC control and protection system;

[0033] Figure 3 It is a schematic diagram of the protection action results under abnormal DC measurement conditions before and after the application of the preventive locking method. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only part of the embodiments of the present invention, not all of them. Based on the spirit of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0035] The present invention utilizes the correlation between different measuring points in the control and protection system to identify whether a single DC measuring point measurement abnormality occurs, and uses the measurement abnormality identification method to optimize the DC protection action export logic to prevent the converter station from being incorrectly locked due to measurement abnormalities.

[0036] like Figure 1 As shown, embodiment 1 of the present invention provides a control and protection system anti-locking method based on abnormal identification of converter station measurement data, comprising the following steps:

[0037] Step S1, real-time measurement of DC measurement point data of each optical fiber current transformer, DC voltage divider and zero flux current transformer in the DC field of at least two control and protection systems in the converter station, wherein the control and protection system includes a duty control and protection system and at least one standby control and protection system. Within the determination period, when it is detected that the change Δ1 of all measurement data of any DC measurement point of the duty control and protection system is greater than the first fixed value ε1, step S2 is executed; otherwise, when the change of all measurement data of any DC measurement point of the duty control and protection system is not greater than the first fixed value, the data of each DC measurement point in the DC field of the converter station continues to be measured.

[0038] In a preferred but non-limiting embodiment of the present invention, the determination period is taken as N≥2 consecutive sampling points collected by the DC measurement device, for example, 5 sampling points are taken as one determination period to avoid misjudgment caused by measurement interference.

[0039] In a preferred but non-limiting embodiment of the present invention, the first set value ε1 is manually set, and the value should be smaller than the starting set value of the DC protection action criterion in which the DC measuring point participates, and is generally set to 0.05-0.08 pu.

[0040] Step S2: If the measurement data change of any DC measuring point in the standby control and protection system or the measurement data change Δ2 of the DC measuring point adjacent to any DC measuring point in the on-duty control and protection system is less than or equal to the first constant ε1 within the judgment period, it is directly determined that a DC measurement abnormality has occurred, the DC protection action signal of the control and protection system associated with the DC measuring point is shielded, and the step is terminated; if the measurement data change Δ2 of the DC measuring point adjacent to any DC measuring point in the on-duty control and protection system is greater than the first constant ε1 within the judgment period, in order to avoid misjudgment during commutation failure and DC line restart, continue to execute step S3.

[0041] In a preferred but non-limiting embodiment of the present invention, adjacent DC measuring point information is obtained according to the primary main wiring diagram of the DC field of the converter station, including the name of each DC measuring point in the converter station, the name of the adjacent DC measuring point and the calculation formula of the indirect calculation value of each DC measuring point based on the adjacent measuring point.

[0042] Taking a typical UHV converter station as an example, according to the primary main connection diagram of the typical UHV converter station, the adjacent DC measurement point information of the converter station is obtained as shown in the following Table 1.

[0043] Table 1 List of adjacent measuring points of converter station

[0044]

[0045]

[0046] Among them, Rd and Rdel are the DC line resistance and grounding electrode lead resistance respectively.

[0047] Step S3, identifying whether a DC measurement abnormality occurs according to the measurement values ​​of the DC measuring points adjacent to any DC measuring point in the on-duty control and protection system, the measurement values ​​of the DC measuring points of the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measuring points. Specifically, by calculating the average value V_MEAN of the measurement value V_MEAS1 of the adjacent DC measuring point of the on-duty control and protection system, the measurement value V_MEAS2 of the DC measuring point of the standby control and protection system, and the indirect calculation value V_CALC of the adjacent DC measuring point, if the absolute value of the difference between the average value V_MEAN and the measurement value V_MEAS of the DC measuring point in the on-duty control and protection system exceeds the second fixed value ε2, it is determined that a DC measurement abnormality occurs; otherwise, it is determined that no DC measurement abnormality occurs.

[0048] In a preferred but non-limiting embodiment of the present invention, the indirect calculation value takes into account the main circuit topology and the randomness of the fault location, and is calculated based on the measurement values ​​of adjacent measurement points.

[0049] Taking a typical UHV converter station as an example, we can refer to the calculation formula provided in the calculation value column in Table 1, substitute the actual measured values ​​of adjacent measuring points, and obtain the indirect calculated value of each measuring point.

[0050] It can be understood that using indirect calculation values ​​calculated in a variety of ways to perform abnormality identification improves the utilization rate of measurement data and can effectively identify abnormal DC measurement data.

[0051] Preferably, the second set value ε2 is set manually, and its value is generally 0.05-0.08 pu.

[0052] Step S4, according to the DC measurement abnormality identification result in step S3, the DC protection action signal of the control and protection system associated with the DC measurement point is shielded or normally executed. The logic block diagram is as follows: Figure 2 Specifically, if the DC measurement abnormality identification result determines that a DC measurement abnormality has occurred, the DC protection action signal associated with the DC measurement point in the DC control and protection system is shielded to avoid DC locking; otherwise, the DC protection signal associated with the DC measurement point in the DC control and protection system is executed normally.

[0053] Embodiment 2 of the present invention provides a control and protection system based on abnormal identification of converter station measurement data, which uses the anti-locking method of the control and protection system based on abnormal identification of converter station measurement data as described in Embodiment 1 to perform exit discrimination of protection action signals, including:

[0054] The DC data detection module is used to measure the data of each DC measuring point in the DC field of the converter station in real time and detect whether the change of the DC measuring point measurement data exceeds the set threshold within the judgment period. The DC measuring point data includes two sets of data of the on-duty control and protection system and the standby control and protection system;

[0055] The adjacent measuring point determination module is used to determine whether the measurement data change of the adjacent DC measuring points exceeds the set threshold;

[0056] An indirect calculation and determination module is used to identify whether a DC measurement abnormality occurs based on the measurement values ​​of the adjacent DC measurement points of the on-duty control and protection system, the measurement values ​​of the DC measurement points of the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measurement points;

[0057] The protection action shielding module is used to shield or normally execute the DC protection action signal associated with the DC measurement point according to the DC measurement abnormality identification result.

[0058] In order to verify the effect of the present invention in practical applications, the following is a specific simulation verification example of the present invention:

[0059] The control and protection system anti-locking method based on converter station measurement data anomaly identification provided in Example 1 of the present invention is applied to a simulation model of a DC control and protection system of a typical UHV converter station, and a measurement anomaly in which the measurement data of a certain DC measurement point is temporarily reduced is simulated at time t1.

[0060] Figure 3 (a) shows the protection action result when the anti-locking method is not put into use. Since the protection action conditions are met, the DC system is locked at time t2. Figure 3 (b) shows the protection action result when the anti-locking method is put into use. Figure 2 As shown in the logic block diagram, since the measurement abnormality identification result is 1, it is input into the AND gate together with the protection action signal after passing through the NOT gate. The final output result of the AND gate is 0, which does not meet the protection action exit condition, so the DC system is not locked.

[0061] Compared with the prior art, the beneficial effects of the present invention include at least:

[0062] (1) The present invention identifies abnormalities in the data of a single DC measurement point based on the multi-source measurement information of the DC control and protection system. The implementation method is simple and reliable, and can directly avoid the risk of DC false locking caused by a single DC measurement abnormality.

[0063] (2) The present invention adopts multiple criteria to determine whether a DC measurement abnormality occurs, accurately identifies abnormal DC measurement data, has higher stability and reliability, and effectively avoids misjudgment of the control and protection system during commutation failure at the converter station and restart of the DC line.

[0064] (3) The present invention uses indirect calculation values ​​calculated in a variety of ways to identify abnormalities, taking into account the randomness of the main circuit topology and the fault location, thereby improving the utilization rate of measurement data and effectively identifying abnormal DC measurement data.

[0065] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A control and protection system anti-locking method based on abnormal identification of converter station measurement data, characterized in that: include: Real-time measurement of the DC measurement point data in at least two control and protection systems in the converter station, wherein the control and protection systems include a duty control and protection system and at least one standby control and protection system; During the determination period, when the changes in all the measurement data of any DC measurement point of the on-duty control and protection system are greater than the first fixed value, if the changes in the measurement data of any DC measurement point of the standby control and protection system or the changes in the measurement data of the DC measurement point adjacent to the any DC measurement point in the on-duty control and protection system is less than or equal to the first fixed value, it is determined that a DC measurement abnormality has occurred, the DC protection action signal of the control and protection system associated with the any DC measurement point is shielded and the determination is terminated; if the changes in the measurement data of the DC measurement points adjacent to the any DC measurement point in the on-duty control and protection system are greater than the first fixed value, whether a DC measurement abnormality has occurred is identified based on the measurement values ​​of the DC measurement points adjacent to the any DC measurement point in the on-duty control and protection system, the measurement values ​​of any DC measurement points in the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measurement points; According to the abnormal identification result of DC measurement, the DC protection action signal of the control and protection system associated with the DC measurement point is shielded or executed normally; During the determination period, when the changes in all measurement data of any DC measurement point of the on-duty control and protection system are not greater than the first set value, continue to measure the data of each DC measurement point in the DC field of the converter station.

2. The anti-locking method of the control and protection system based on abnormal identification of converter station measurement data according to claim 1 is characterized in that: The determination period is set to be N≥2 consecutive sampling points.

3. The anti-locking method of the control and protection system based on abnormal identification of converter station measurement data according to claim 1 is characterized in that: The first set value ε1 is smaller than the starting set value of the DC protection action criterion in which the DC measuring point participates.

4. The DC control and protection system anti-locking method based on converter station DC measurement data abnormality identification according to claim 3 is characterized in that: The first constant ε1 is set to be 0.05-0.08 pu.

5. The control and protection system anti-locking method based on converter station measurement data abnormality identification according to claim 1 is characterized in that: Determine the calculation formula of adjacent DC measuring points and indirect calculation values ​​according to the primary main wiring diagram of the DC field of the converter station.

6. The control and protection system anti-locking method based on converter station measurement data abnormality identification according to claim 1 is characterized in that: The indirect calculation value takes into account the main circuit topology and the randomness of the fault location, and is calculated based on the measurement values ​​of adjacent measuring points.

7. The control and protection system anti-locking method based on converter station measurement data abnormality identification according to claim 1 is characterized in that: Identifying whether a DC measurement abnormality occurs according to the measurement value of a DC measurement point adjacent to any DC measurement point in the duty control and protection system, the measurement value of any DC measurement point in the standby control and protection system, and the indirect calculation value based on the adjacent DC measurement point specifically includes: Calculate the average value V_MEAN of the measured value V_MEAS1 of the adjacent DC measuring point in the on-duty control and protection system, the measured value V_MEAS2 of the DC measuring point in the standby control and protection system, and the indirect calculated value V_CALC of the adjacent measuring point. If the absolute value of the difference between the average value V_MEAN and the measured value V_MEAS of the DC measuring point in the on-duty control and protection system exceeds the second fixed value ε2, it is determined that a DC measurement abnormality has occurred; otherwise, it is determined that no DC measurement abnormality has occurred.

8. The control and protection system anti-locking method based on converter station measurement data abnormality identification according to claim 7 is characterized in that: The second constant ε2 is set to be 0.05-0.08 pu.

9. The control and protection system anti-locking method based on converter station measurement data abnormality identification according to claim 1 is characterized in that: According to the abnormal DC measurement identification result, the DC protection action signal of the control and protection system associated with the DC measurement point is shielded or normally executed, specifically including: If the DC measurement abnormality identification result determines that a DC measurement abnormality has occurred, the DC protection action signal associated with the DC measurement point in the DC control and protection system is shielded. Otherwise, the DC protection signal associated with the DC measurement point in the DC control and protection system is executed normally.

10. A control and protection system based on abnormal identification of converter station measurement data, using the anti-locking method of the control and protection system based on abnormal identification of converter station measurement data as described in any one of claims 1 to 9 to perform exit discrimination of protection action signals, characterized in that: include: The DC data detection module is used to measure the data of each DC measuring point in the DC field of the converter station in real time and detect whether the change of the DC measuring point measurement data exceeds the set threshold within the judgment period. The DC measuring point data includes two sets of data of the on-duty control and protection system and the standby control and protection system; The adjacent measuring point determination module is used to determine whether the measurement data change of the adjacent DC measuring points exceeds the set threshold; An indirect calculation and determination module is used to identify whether a DC measurement abnormality occurs based on the measurement values ​​of the adjacent DC measurement points of the on-duty control and protection system, the measurement values ​​of the DC measurement points of the standby control and protection system, and the indirect calculation values ​​based on the adjacent DC measurement points; The protection action shielding module is used to shield or normally execute the DC protection action signal associated with the DC measurement point according to the DC measurement abnormality identification result.

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