Control and protection system anti-blocking method based on converter station measurement data anomaly identification

Abstract

The application discloses a control and protection system anti-blocking method based on converter station measurement data anomaly identification, which comprises the following steps: measuring the data of each direct-current measuring point in at least two sets of control and protection systems in a converter station in real time; when the change amount of all the measurement data of any direct-current measuring point of the on-duty control and protection system is greater than a first fixed value in a judgment period, if the change amount of the measurement data of any direct-current measuring point of the standby control and protection system or the change amount of the measurement data of the direct-current measuring point adjacent to the any direct-current measuring point of the on-duty control and protection system is less than or equal to the first fixed value, it is determined that a direct-current measurement anomaly occurs; otherwise, whether the direct-current measurement anomaly occurs is identified according to the measurement value of the adjacent direct-current measuring point, the measurement value of the standby control and protection system and an indirectly calculated value; and the direct-current protection action signal of the control and protection system associated with the direct-current measuring point is shielded or normally executed according to the identification result. The application avoids the risk that the direct-current blocking is caused by the direct-current measurement anomaly of a single measuring point.

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-lockout method for a control and protection system based on abnormal identification of converter station measurement data. Background Art

[0002] DC measurement equipment provides primary electrical quantity signals for the control and protection systems of UHV converter stations. 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 measurement equipment such as pure optical transformers, zero-flux CTs, DC voltage dividers, and electronic transformers are commonly used in DC transmission projects. However, these devices differ from the principles of traditional electromagnetic transformers, and the reliability of these devices is still insufficient.

[0003] Although redundant configurations of the DC control and protection system and its DC measurement secondary circuits effectively reduce the risk of malfunction or failure of the control and protection system due to DC measurement secondary circuit failures, abnormal DC measurement data still frequently occur when the DC measurement primary equipment is affected by external interference, making malfunction of the control and protection system difficult to avoid. During converter station operation, converter transformer lockouts have occurred repeatedly due to measurement anomalies in a single measurement device. The primary cause of DC lockouts with existing DC measurement equipment is the inability of the DC control and protection system to effectively identify abnormal DC measurement data.

[0004] Due to the persistent problem of DC measurement equipment causing converter station lockouts in recent years, researchers at home and abroad have conducted extensive research on the problem of DC measurement equipment failures. However, this research has mainly focused on the status assessment, fault diagnosis, and reliability improvement of DC measurement equipment such as optical CTs. There is currently no method in the existing technology to fundamentally eliminate the problem of DC measurement equipment failures. Some research has involved the problem of DC lockouts caused by abnormal DC measurement data in converter stations, but this has mainly focused 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 and protection. Summary of the Invention

[0005] To address the deficiencies in the prior art, the present invention provides a control and protection system anti-lockout method based on converter station measurement data anomaly identification. This method, based on the difference between the measurement anomaly of a single DC measuring point and the electrical characteristic quantities after an actual converter station fault, implements measurement data anomaly identification through information comparison and verification at different measuring points, thereby avoiding the risk of DC lockout in DC transmission projects caused by DC measurement anomalies at a single measuring point.

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

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

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

[0009] During the determination period, when the amount of change of all measurement data of any DC measurement point of the on-duty control and protection system is greater than a first fixed value, if the amount of change of measurement data of any DC measurement point in the standby control and protection system or the amount of change of measurement data of a DC measurement point adjacent to the said 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 said any DC measurement point is shielded and the determination is terminated; if the amount of change of measurement data of the DC measurement points adjacent to the said any DC measurement point in the on-duty control and protection system is greater than the first fixed value, whether a DC measurement abnormality has occurred is identified based on the measurement value of the DC measurement point adjacent to the said 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;

[0010] Based on the DC measurement anomaly identification results, 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 constant ε1 is smaller than the starting constant of the DC protection action criterion in which the DC measuring point participates.

[0014] Preferably, the first constant ε1 is set to 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 connection diagram of the DC field of the converter station.

[0016] Preferably, the indirect calculated 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.

[0017] Preferably, identifying whether a DC measurement abnormality occurs based on the measurement value of a DC measurement point adjacent to the 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 an 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 of the on-duty control and protection system, the measured value V_MEAS2 of the DC measuring point of 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 value ε2 is set to 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 will be shielded. Otherwise, the DC protection signal associated with the DC measurement point in the DC control and protection system will be executed normally.

[0022] A second aspect of the present invention provides a control and protection system based on converter station measurement data anomaly identification, which uses the control and protection system anti-lockout method based on converter station measurement data anomaly identification to perform output discrimination of protection action signals, including:

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

[0024] Adjacent measuring point determination module, used to determine whether the change in measurement data of adjacent DC measuring points exceeds a set threshold;

[0025] An indirect calculation and judgment module is used to identify whether a DC measurement anomaly 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 execute normally 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 anomalies, 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 This is a flow chart of the anti-lockout 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] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying 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 making creative efforts 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 anomaly occurs, and uses the measurement anomaly identification method to optimize the DC protection action output logic to prevent the converter station from being incorrectly locked due to measurement anomalies.

[0036] like Figure 1 As shown, embodiment 1 of the present invention provides a control and protection system anti-lockout 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 an on-duty control and protection system and at least one standby control and protection system. Within a determination period, when it is detected that the change Δ1 of all measurement data of any DC measurement point of the on-duty control and protection system is greater than a first fixed value ε1, step S2 is executed; otherwise, when the change of all measurement data of any DC measurement point of the on-duty control and protection system is not greater than the first fixed value, the measurement of the DC measurement point data of the DC field in the converter station continues.

[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 its 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] In 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 the said DC measuring point in the on-duty control and protection system is less than or equal to the first fixed value 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 the said DC measuring point in the on-duty control and protection system is greater than the first fixed value ε1 within the judgment period, in order to avoid misjudgment during commutation failure and DC line restart, step S3 is continued.

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

[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 stations

[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 has occurred 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 the DC measurement points in the standby control and protection system, and the indirectly calculated values ​​based on the adjacent DC measurement points. Specifically, by calculating the average value V_MEAN of the measurement value V_MEAS1 of the adjacent DC measurement point in the on-duty control and protection system, the measurement value V_MEAS2 of the DC measurement point in the standby control and protection system, and the indirectly calculated value V_CALC of the adjacent DC measurement point, if the absolute value of the difference between the average value V_MEAN and the measurement value V_MEAS of the DC measurement point in the on-duty control and protection system exceeds a 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.

[0048] In a preferred but non-limiting embodiment of the present invention, the indirect calculated 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 constant value ε2 is set manually, and is generally 0.05 to 0.08 pu.

[0052] Step S4, based on 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 executed normally. The logic block diagram is as follows: Figure 2 Specifically, if the DC measurement anomaly identification result indicates a DC measurement anomaly, the DC protection action signal associated with the DC measurement point in the DC control and protection system is shielded to prevent DC blocking; 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-lockout method of the control and protection system based on abnormal identification of converter station measurement data as described in Embodiment 1 to perform output discrimination of protection action signals, including:

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

[0055] Adjacent measuring point determination module, used to determine whether the change in measurement data of adjacent DC measuring points exceeds a set threshold;

[0056] An indirect calculation and judgment module is used to identify whether a DC measurement anomaly 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 execute normally 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-lockout 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-lockout method is not used. 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. Therefore, 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 anomalies, 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 can be a system, a method, and / or a computer program product. The computer program product can include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure.

[0066] It should be noted that the above-mentioned embodiments are only used to illustrate the technical solutions of the present application, not to limit it. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or equivalent replaced without departing from the spirit and scope of the present application. Any modification or equivalent replacement should be covered within the protection scope of the claims of the present application.

Claims

1. A control and protection system anti-lockout method based on abnormal identification of converter station measurement data, characterized in that: include: Real-time measurement of DC measurement point data in at least two control and protection systems within the converter station, where the control and protection systems include an on-duty control and protection system and at least one standby control and protection system; 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 greater than a first fixed value, and if the changes in measurement data of any DC measurement point of the standby control and protection system or the changes in measurement data of a DC measurement point adjacent to the said DC measurement point in the on-duty control and protection system are 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 said DC measurement point is shielded, and the operation is terminated; If the changes in the measurement data of the DC measurement points adjacent to any of the DC measurement points in the on-duty control and protection system are all greater than a first fixed value, then the average of the measurement values ​​of the adjacent DC measurement points in the on-duty control and protection system, the measurement values ​​of the DC measurement points in the standby control and protection system, and the indirect calculation values ​​of the adjacent DC measurement points are calculated. If the absolute value of the difference between the average value and the measurement value of the DC measurement point in the on-duty control and protection system exceeds a second fixed value, it is determined that a DC measurement abnormality has occurred; Otherwise, it is determined that no DC measurement abnormality has occurred; Based on the DC measurement anomaly identification results, 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-lockout method for a 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-lockout method for a 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 anti-lockout method for a control and protection system based on abnormal identification of converter station measurement data according to claim 3 is characterized in that: The first constant ε1 is set to 0.05-0.08 pu.

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

6. The control and protection system anti-lockout method based on converter station measurement data anomaly 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-lockout method based on converter station measurement data anomaly identification according to claim 1 is characterized in that: The second constant value ε2 is set to 0.05-0.08 pu.

8. The control and protection system anti-lockout method based on converter station measurement data anomaly identification according to claim 1 is characterized in that: Based on the DC measurement anomaly identification results, the DC protection action signal of the control and protection system associated with the DC measurement point is shielded or executed normally, 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 will be shielded. Otherwise, the DC protection signal associated with the DC measurement point in the DC control and protection system will be executed normally.

9. A control and protection system based on abnormal identification of converter station measurement data, using the anti-locking method of a control and protection system based on abnormal identification of converter station measurement data according to any one of claims 1 to 8 to perform output discrimination of protection action signals, characterized in that: include: The DC data detection module is used to measure the data of each DC measurement point in the DC field of the converter station in real time and detect whether the change in the DC measurement data exceeds the set threshold within the judgment period. The DC measurement point data includes two sets of data: the on-duty control and protection system and the standby control and protection system. Adjacent measuring point determination module, used to determine whether the change in measurement data of adjacent DC measuring points exceeds a set threshold; An indirect calculation and judgment module is used to identify whether a DC measurement anomaly 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 execute normally the DC protection action signal associated with the DC measurement point according to the DC measurement abnormality identification result.

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