A method and system for detecting the working state of a relay protection trip-closing circuit

Abstract

This invention discloses a method and system for detecting the operating status of a tripping and closing circuit in a relay protection system. The method includes: connecting a Hall current sensor to the tripping and closing circuit of the relay protection operating circuit; detecting the operating status of the tripping and closing circuit based on the Hall effect principle; setting the output voltage setting value of the tripping and closing circuit; acquiring the secondary output voltage of the Hall effect sensor after the tripping and closing circuit is turned on; comparing the acquired secondary output voltage of the Hall effect sensor with the output voltage setting value to determine the operating status of the tripping and closing circuit; when the tripping and closing circuit is in the on state, determining whether it is a valid trip based on whether the voltage at the front end of the tripping and closing coil changes abruptly; and comparing the operating status of the output circuit detected by the Hall current sensor with the tripping and closing command issued by the relay protection device to determine whether the operating condition of the output circuit is abnormal. This invention can improve the accuracy of operating circuit monitoring and reduce the impact on circuit operation.

Description

Technical Field

[0001] This invention relates to the technical field of power system fault detection, and more specifically, to a method and system for detecting the working status of the tripping and closing circuits of relay protection. Background Technology

[0002] The DC operating circuit is used to operate and control primary equipment in power systems such as circuit breakers, playing a crucial role in relay protection systems. It consists of numerous relays and equipment connection cables. Currently, the DC operating circuits in relay protection systems that perform operation and control functions lack online self-testing, real-time monitoring, and remote information transmission capabilities. Furthermore, existing secondary control circuit control boxes do not meet the requirements for condition-based maintenance of equipment. Therefore, for DC operating circuits that directly operate trip or close commands, there is no effective means to directly detect their operating status and operation. It is necessary to implement online monitoring methods to achieve online monitoring of the DC operating circuit's operating status and wiring.

[0003] Poor contact and circuit breakage are common problems in DC operating circuits. Conventional methods such as direct monitoring of traffic light circuits or indirect monitoring via normally closed contacts of position relays connected in series with signal circuits are not full-condition monitoring methods. This means that after the circuit breaker closes (trips), the closing (tripping) circuit loses monitoring, compromising power supply reliability. Burnout of tripping and closing circuit components is a significant cause of DC operating circuit breakage. When a circuit breaker fails to operate or an auxiliary switch malfunctions, components such as tripping and closing coils or relays will burn out due to prolonged operating current. Since most substations are currently unmanned, protection systems do not issue signals in these situations until a "control circuit breakage" warning is issued by the dispatching terminal after the tripping and closing circuit components have burned out. To meet the demands of building a smart grid in my country, online monitoring of power system equipment and circuits is a crucial measure to achieve this goal. Simultaneously, the continuous improvement in the reliability of electronic components makes the application of online monitoring methods and measures possible. Some literature proposes a trip circuit disconnection monitoring scheme using a series high-resistance relay, but the closing circuit remains in a non-full-condition mode. Other scholars have proposed a dual-function approach for secondary circuit protection and integrity monitoring. Existing technical literature introduces the concept of intelligent control boxes, but their use in conventional substations is both inefficient and increases system complexity. Currently, there is no mature method to achieve comprehensive and effective monitoring of DC control circuits. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for detecting the operating status of the tripping and closing circuit of a relay protection system, which can conveniently and safely achieve accurate monitoring of the output status of the relay protection operating circuit.

[0005] Detect faults at the output of the relay protection operation circuit.

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

[0007] A method for detecting the operating status of a relay protection tripping and closing circuit includes the following steps:

[0008] Step 1: Connect the Hall current sensor to the trip and close circuit of the relay protection operation circuit, and detect the working status of the trip and close circuit based on the Hall effect principle.

[0009] Step 2, set the output voltage setting value U of the trip and close circuit. set ;

[0010] Step 3: Obtain the secondary output voltage U of the Hall effect sensor after the trip-close circuit is turned on. out ;

[0011] Step 4: Compare the secondary output voltage of the Hall effect sensor with the output voltage setting value to determine whether the trip-close circuit is conducting normally.

[0012] Step 5: When the trip-closing circuit is in normal conduction mode, determine whether the trip is effective based on whether the voltage at the front end of the trip-closing coil changes abruptly. If the result is effective trip, proceed to step 6.

[0013] Step 6: Compare the trip and close circuit operating status detected by the Hall current sensor obtained in Step 1 with the trip and close command issued by the relay protection device to determine whether the trip and close circuit operating status of the operation circuit is abnormal.

[0014] Preferably, step 1 further includes,

[0015] When it is necessary to monitor the output circuit of a single trip-close circuit, the output circuit cable of the trip-close circuit is threaded through a hole and the Hall current sensor is passed through to connect the Hall current sensor to the output circuit cable of the trip-close circuit.

[0016] When it is necessary to monitor the output circuits of multiple trip and close circuits simultaneously, the output circuits to be monitored are numbered sequentially. Suppose that N output circuits need to be monitored, then for the Xth output circuit number, X∈[1, N], the output circuit cable is wound around a Hall current sensor for 2... x-1 This allows for the connection between the output circuit of each trip and close circuit and the Hall current sensor.

[0017] Preferably, the set output voltage setting value U set satisfy:

[0018] U set=K*I*P

[0019] Where K is the current detection weighting coefficient, I is the detection current, and P is the conversion coefficient between the detection current I and the voltage.

[0020] Preferably, the current detection weighting coefficient K is calculated using the following formula:

[0021] K = 1 - N * lnT / 30

[0022] Where N is the number of times the circuit breaker is opened and closed, and T is the service life, with T in years;

[0023] The number of opening and closing cycles, N, is recorded by a counter;

[0024] If a year is set to 365 days, then the value of T is: service duration days / 365.

[0025] Preferably, in step 3:

[0026] When monitoring a single protection circuit, the secondary output voltage U of the Hall current sensor connected to that circuit... out satisfy:

[0027] U out =I*P

[0028] When monitoring multiple protection circuits simultaneously, the output circuits to be monitored are numbered sequentially, let's call the output circuit number X. The output circuit cables are wound around a Hall current sensor with 2... x-1 The loop. With this special winding method, when the Xth output loop is turned on, the secondary output voltage U of the Hall current sensor connected to that loop... out Satisfy the following formula:

[0029] U out =2 x-1 *I*P

[0030] Where I is the detection current and P is the conversion coefficient between the detection current I and the voltage.

[0031] Preferably, in step 4:

[0032] If U out ≥U set If the output voltage is greater than the preset output voltage setting value, then the trip-close circuit is judged to be normally connected.

[0033] If U out <U set If the output voltage is less than the preset output voltage setting value, the trip / close circuit is judged to be abnormally connected.

[0034] Preferably, step 5 further includes: setting an effective value for voltage fluctuation. When the trip-closing circuit is in the working state and the voltage at the front end of the trip-closing coil changes suddenly, and the change in voltage is greater than or equal to the effective value of voltage fluctuation, it is determined to be a valid trip.

[0035] Preferably, the effective value of the voltage surge is set to 90% of the rated voltage of the operating circuit.

[0036] Preferably, step 6 further includes:

[0037] If the operating status of the trip and close circuit is inconsistent with the trip and close command, it is determined that the trip and close circuit is in an abnormal operating condition and a signal is sent to the protection device.

[0038] If the operating status of the trip and close circuit is consistent with the trip and close command, it is determined that the trip and close circuit is in normal operating condition and no signal is sent to the protection device.

[0039] The present invention also provides a relay protection tripping and closing circuit working status detection system, which includes a detection module, a calculation module, a parameter acquisition module and a judgment module;

[0040] The detection module includes a Hall current sensor, which is connected to the trip and close circuit of the relay protection operation circuit and can detect the working status of the output circuit of the trip and close circuit.

[0041] The calculation module is used to calculate the set value of the output voltage of the trip-close circuit and to obtain the secondary output voltage of the Hall effect sensor after the trip-close circuit is turned on.

[0042] The parameter acquisition module is used to acquire the voltage change value when the voltage at the front end of the trip and close coil suddenly changes, as well as the trip and close commands issued by the relay protection device.

[0043] The judgment module can determine the working status of the trip and close circuit, whether the trip of the trip and close circuit is a valid trip, and whether the working condition of the trip and close circuit is abnormal based on the data obtained by the Hall current sensor, the calculation module, and the parameter acquisition module.

[0044] The beneficial effects of this invention are that, compared with the prior art, the relay protection tripping and closing circuit operation status detection method and system disclosed in this invention can meet the EMC requirements of power systems, i.e., it is unaffected by surge and fast transient interference, and can resist classical interference; it significantly improves the monitoring capability of the operating circuit, improves the monitoring accuracy to 0.1V, and achieves synchronous voltage sampling, i.e., simultaneous cross-sectional sampling of each channel. The sampling rate reaches 1kHz per second. This invention includes at least the following beneficial effects:

[0045] 1. This invention constructs a method for monitoring the voltage and current micro-disturbances of key nodes in the operating circuit, which is more intelligent and convenient than existing multimeter monitoring methods and safer than existing series monitoring schemes.

[0046] 2. Currently, the channel resources of the switch in the station are limited, the remaining network ports are limited, and the switch is not deployed in the switch room, which restricts the wiring scheme due to distance. Therefore, in order to address the problem of difficult network setup of switch cabinets, this invention constructs a node-based switching interaction scheme. Relying on the redundant remote signaling nodes of the switch cabinet with existing protection devices, the monitoring results are sent up through signal redefinition, realizing information transmission based on the existing protection and monitoring devices. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the overall process of the relay protection tripping and closing circuit working status detection method of the present invention;

[0048] Figure 2 This is a schematic diagram of the operating circuit of the relay protection in this invention;

[0049] Figure 3 This is a schematic diagram of the overall structure of the relay protection tripping and closing circuit working status detection system of the present invention. Detailed Implementation

[0050] The present application will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and should not be construed as limiting the scope of protection of the present application.

[0051] like Figure 1 As shown, this invention proposes a method for detecting the operating status of the tripping and closing circuit of a relay protection system. This method specifically includes the following steps:

[0052] Step 1: Connect the Hall current sensor to the trip and close circuit of the relay protection operation circuit, and detect the working status of the trip and close circuit based on the Hall effect principle.

[0053] Specifically, the Hall current sensor is connected to the trip and close circuit of the relay protection operation circuit, and the Hall current sensor is used to detect the current in the trip and close circuit. By utilizing the difference in the output voltage of the Hall current sensor when the relay protection operation circuit is turned on and off, the working status detection criterion of the trip and close circuit based on the Hall effect principle is realized.

[0054] When it is necessary to monitor a single trip-close circuit, the outlet circuit cable of the trip-close circuit is threaded through a hole and a Hall current sensor is passed through to connect the Hall current sensor to the trip-close circuit.

[0055] When multiple tripping and closing circuits need to be monitored simultaneously, the output circuits of the tripping and closing circuits to be monitored are numbered sequentially. Suppose N tripping and closing circuits need to be monitored. Then, for the output circuit of the Xth tripping and closing circuit, where X∈[1, N], the output circuit cable is wound around a Hall current sensor for 2... x-1 This allows for the connection of each trip and close circuit with the Hall current sensor.

[0056] Step 2: Set the output voltage setting value of the trip and close circuit;

[0057] Specifically, the output voltage setting value U set in this invention set satisfy:

[0058] U set =K*I*P

[0059] Where K is the current detection weighting coefficient, I is the detection current, and P is the conversion coefficient between the detection current I and the voltage.

[0060] Furthermore, the current detection weighting coefficient K is determined based on the service life of the relay protection operating circuit and the number of opening and closing cycles. The current detection weighting coefficient K should satisfy the following attenuation curve formula:

[0061] K = 1 - N * lnT / 30

[0062] Where N is the number of times the circuit breaker is opened and closed, and T is the service life, with T in years.

[0063] Specifically, the number of opening and closing times N can be recorded by a counter. An initial value can be pre-entered, and the counter will automatically record once each change is detected.

[0064] The value of T is accurate to the number of days. In this invention, a year is set to 365 days, so the value of T is: service duration in days / 365.

[0065] Furthermore, the detection current I can be generated by a weak signal generator. In this invention, the weak signal generator is connected to the trip-close circuit so that the detection current I is injected into the trip-close circuit. The detection current I needs to meet the requirement that the current magnitude is less than 0.1 mA, and the operating voltage of the weak signal generator is set to 3.3V.

[0066] like Figure 2 As shown, the conversion coefficient P between the detected current I and the voltage in this invention ranges from 0.75 to 0.9. The specific value of P is related to the impedance of the operating circuit and the external mechanism box. Therefore, the specific value of P should be adjusted and confirmed by those skilled in the art based on the actual situation.

[0067] Step 3: Obtain the secondary output voltage of the Hall effect sensor after the trip-close circuit is turned on;

[0068] Those skilled in the art should understand that the state of the trip-close circuit is controlled by the relay protection device. When the relay protection device issues a trip-close command, the trip-close relay contacts close, and current flows through the trip-close circuit. Therefore, the secondary output voltage of the Hall current sensor is U. out Changes will occur.

[0069] When monitoring a single protection circuit, the secondary output voltage U of the Hall current sensor connected to that circuit... out satisfy:

[0070] U out =I*P

[0071] When monitoring multiple protection circuits simultaneously, the output circuits to be monitored are numbered sequentially, let's call the output circuit number X. The output circuit cables are wound around a Hall current sensor with 2... x-1 The loop. With this special winding method, when the Xth output loop is turned on, the secondary output voltage U of the Hall current sensor connected to that loop... out Satisfy the following formula:

[0072] U out =2 x-1 *I*P

[0073] Step 4: Compare the secondary output voltage of the Hall effect sensor with the output voltage setting value to determine whether the trip-close circuit is conducting normally.

[0074] Specifically, if U out ≥U set If the output voltage is greater than the preset output voltage setting value, then the trip-close circuit is judged to be normally connected.

[0075] If U out <U set If the output voltage is less than the preset output voltage setting value, the trip / close circuit is judged to be abnormally connected.

[0076] Step 5: When the trip-closing circuit is in normal conduction mode, determine whether the trip is effective based on whether the voltage at the front end of the trip-closing coil changes abruptly. If the result is effective trip, proceed to step 6.

[0077] Specifically, an effective value for voltage fluctuation is set. When the trip-closing circuit is in the working state and conducting, if the voltage at the front end of the trip-closing coil changes suddenly, and the change in voltage is greater than the effective value of voltage fluctuation, it is considered a valid trip.

[0078] The effective value of voltage mutation is 90% of the rated voltage of the operating circuit. Taking a 220V operating circuit as an example, the effective mutation value is 198V.

[0079] Step 6: Compare the trip and close circuit operating status detected by the Hall current sensor obtained in Step 1 with the trip and close command issued by the relay protection device to determine whether the trip and close circuit operating status of the operation circuit is abnormal.

[0080] If the operating status of the trip and close circuit is inconsistent with the trip and close command, the trip and close circuit is judged to be in an abnormal operating condition and an abnormal signal is sent to the protection device.

[0081] If the operating status of the trip and close circuit is consistent with the trip and close command, then the trip and close circuit is judged to be in normal operating condition and no abnormal signal is sent to the protection device.

[0082] The present invention also provides a relay protection trip and close circuit working status detection system. The above-mentioned relay protection trip and close circuit working status detection method can be implemented based on the system. Specifically, the system includes a detection module, a calculation module, a parameter acquisition module and a judgment module.

[0083] The detection module includes a Hall current sensor, which is connected to the trip and close circuit of the relay protection operation circuit and can detect the working status of the output circuit of the trip and close circuit.

[0084] The calculation module is used to calculate the set value of the output voltage of the trip-close circuit and to obtain the secondary output voltage of the Hall effect sensor after the trip-close circuit is turned on.

[0085] The parameter acquisition module is used to acquire the voltage change value when the voltage at the front end of the trip and close coil suddenly changes, as well as the trip and close commands issued by the relay protection device.

[0086] The judgment module can determine the working status of the trip and close circuit, whether the trip of the trip and close circuit is a valid trip, and whether the working condition of the trip and close circuit is abnormal based on the data obtained by the Hall current sensor, the calculation module, and the parameter acquisition module.

[0087] The beneficial effects of this invention are that, compared with the prior art, this invention is not affected by surges and rapid transients during the detection process, and can resist classical interference, thereby greatly improving the monitoring capability of the operating circuit and improving the monitoring accuracy.

[0088] The applicant of this invention has provided a detailed description of the embodiments of the invention in conjunction with the accompanying drawings. However, those skilled in the art should understand that the above embodiments are merely preferred embodiments of the invention. The detailed description is only intended to help readers better understand the spirit of the invention and is not intended to limit the scope of protection of the invention. On the contrary, any improvements or modifications made based on the inventive spirit of the invention should fall within the scope of protection of the invention.

Claims

1. A method for detecting the operating state of a relay protection tripping circuit, characterized in that, The method comprises the following steps: Step 1, connect the Hall current sensor with the tripping and closing circuit of the relay protection operation circuit, and detect the working state of the tripping and closing circuit based on the Hall effect principle; Step 2, set the output voltage setting value U of the trip-closing circuit set ; The set output voltage setting value U set satisfies: U set = K * I * P Wherein, K is the current detection weight coefficient, I is the detection current, and P is the transformation coefficient of the detection current I and the voltage; The calculation formula of the current detection weight coefficient K is as follows: K = 1 - N * lnT / 30 Wherein, N is the number of tripping and closing, and T is the service time, and T is in units of years; Step 3, obtain the secondary output voltage U of the Hall effect sensor after the jump closing circuit is turned on out ; Step 4, compare the obtained secondary output voltage of the Hall effect sensor with the output voltage setting value, and judge whether the conduction of the tripping and closing circuit is normal; Step 5, when the working state of the tripping and closing circuit is normal conduction, judge whether it is effective tripping according to whether the front-end voltage of the tripping and closing coil is suddenly changed, and if the judgment result is effective tripping, go to step 6; Step 6, compare the working state of the tripping and closing circuit detected by the Hall current sensor obtained in step 1 with the tripping and closing command issued by the relay protection device, and judge whether the working condition of the tripping and closing circuit of the operation circuit is abnormal.

2. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, the step 1 further comprises, when it is necessary to monitor the outlet circuit of a single tripping and closing circuit, the outlet circuit cable of the tripping and closing circuit is perforated through the Hall current sensor to realize the connection of the Hall current sensor and the outlet circuit cable of the tripping and closing circuit; When the outlet circuits of multiple trip-closing circuits need to be monitored simultaneously, the outlet circuits to be detected are numbered in sequence, and it is assumed that N outlet circuits of trip-closing circuits need to be monitored, then for the Xth outlet circuit number, X∈[1, N], the outlet circuit cable is wound around a Hall current sensor twice, thereby realizing the connection of the outlet circuits of the trip-closing circuits with the Hall current sensor. x-1 circle, thereby realizing the connection of the outlet circuits of the trip-closing circuits with the Hall current sensor.

3. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, the number of tripping and closing N is recorded by a counter; 365 days are set as one year, and the value of T is: service time (days) / 365.

4. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, in the step 3, When monitoring a single protective circuit, the secondary output voltage U of the Hall current sensor connected to the circuit out satisfies: U out = I * P When monitoring the multiple protection circuits simultaneously, the outlet circuits to be detected are numbered in sequence, and the outlet circuit cable is wound 2 x-1 times around a Hall current sensor. After adopting this special winding method, when the Xth outlet circuit is turned on, the secondary output voltage U out of the Hall current sensor connected to the circuit satisfies the following formula: U out = 2 x-1 *I*P wherein, I is the detection current, and P is the transformation coefficient of the detection current I and the voltage.

5. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, in the step 4, If U out ≥ U set , that is, the output voltage is greater than the preset output voltage setting value, it is judged that the trip-closing circuit is normally turned on. If U out <U set If the output voltage is less than the preset output voltage setting value, it is determined that the trip-closing circuit is not normally on.

6. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, the step 5 further comprises: setting the effective value of voltage sudden change, and in the case that the working state of the tripping and closing circuit is conduction, if the front-end voltage of the tripping and closing coil is suddenly changed and the change value of the voltage is greater than or equal to the effective value of voltage sudden change, it is judged as effective tripping.

7. The relay protection tripping and closing circuit working state detection method according to claim 6, characterized in that, the effective value of voltage sudden change is set as 90% of the rated voltage of the operation circuit.

8. The relay protection tripping and closing circuit working state detection method according to claim 1, characterized in that, the step 6 further comprises: if the working state of the tripping and closing circuit is inconsistent with the tripping and closing command, it is judged that the tripping and closing circuit is in abnormal working condition, and a signal is sent to the protection device; if the working state of the tripping and closing circuit is consistent with the tripping and closing command, it is judged that the tripping and closing circuit is in normal working condition, and no signal is sent to the protection device.

9. A system for detecting the operating state of a trip-closing circuit of a relay protection according to any one of claims 1 to 8, characterized in that, comprise: a detection module, a calculation module, a parameter acquisition module and a judgment module; The detection module comprises a Hall current sensor connected with a tripping and closing circuit of the relay protection operation circuit, and is capable of detecting an outlet circuit working state of the tripping and closing circuit. The calculation module is used for calculating a set output voltage setting value of the tripping and closing circuit and acquiring a secondary output voltage of the Hall effect sensor after the tripping and closing circuit is turned on. The parameter acquisition module is used for acquiring a voltage change value when a front-end voltage of the tripping and closing coil suddenly changes and a tripping and closing command issued by the relay protection device. The judgment module is capable of judging a working state of the tripping and closing circuit, whether tripping of the tripping and closing circuit is effective tripping and whether a working condition of the tripping and closing circuit is abnormal according to data obtained by the Hall current sensor, the calculation module and the parameter acquisition module.

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