An automatic calibration algorithm for motor startup monitoring and protection based on multithreading

Abstract

The present invention discloses an automatic calibration algorithm for motor startup monitoring and protection based on multi-threading, a relay protection device for motor startup detection, a relay protection tester for simulating secondary side faults in a substation, and an external computer installed with a Windows system. Among them, the method includes the following steps: S1: Connecting the closed-loop test system, S2: Tuning the state parameters of the startup monitoring unit, and S3: Controlling the output excitation of the tester. The present invention can not only ensure the safety and reliability of the joint calibration of the relay protection device and the microcomputer relay protection tester in a closed loop, but also achieve high responsiveness to complete automatic testing and eliminate the randomness of test results.

Description

Technical Field

[0001] The present invention relates to the technical field of motor starting monitoring and protection automatic verification, and particularly relates to a multi-threaded based motor starting monitoring and protection automatic verification algorithm. Background Art

[0002] As is well known, a relay protection device is a secondary device that can timely send a warning to the on-duty operator or directly control the circuit breaker to trip to terminate the development of a fault when a power component or the power system itself in the power system fails and endangers the safe operation of the power system. It plays a crucial role in the safe operation of the power system and directly affects the safety and stable operation of the system. Therefore, maintaining the protection device, eliminating device anomalies and fault defects are important tasks in power system maintenance.

[0003] Traditional relay protection testing is mainly completed by the cooperation of a voltage regulator and a phase shifter. The voltage regulator is mainly composed of thyristors and transformer coils and is responsible for setting the input excitation voltage, current and power to be tested; the phase shifter can cooperate to shift the phase of the input excitation waveform, thereby realizing the verification of the relay protection device. However, the operation mode of traditional testing tools is complex, the accuracy is not high and the volume is bulky, making it difficult to adapt to the verification work of the new generation of microcomputer relay protection devices.

[0004] Currently, relay protection testing mainly conducts standardized relay protection testing by setting the test parameter table of a microcomputer relay protection tester. With the birth of the microcomputer relay protection tester, the objects under test in relay protection verification work also have intelligent features and have functions such as remote status control, action reset and remote setting verification through an external computer.

[0005] However, in the existing verification procedures, only the microcomputer relay protection tester can be set. There is still no effective solution for the joint verification of the relay protection device and the microcomputer relay protection tester in a closed loop due to high requirements for safety and reliability. For the verification of motor starting monitoring and protection, since the state register parameters of the protection device need to be frequently modified, the single-setting manual test duration is more than 20 minutes, and the test results are single and it is difficult to eliminate random errors. Therefore, ensuring the safety and reliability of the joint verification of the relay protection device and the microcomputer relay protection tester in a closed loop and achieving high responsiveness to complete automatic testing and eliminate the randomness of test results are problems that need to be urgently solved by the technical personnel at the present stage. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a multi-threaded based motor starting monitoring and protection automatic verification algorithm, which can not only ensure the safety and reliability of the joint verification of the relay protection device and the microcomputer relay protection tester in a closed loop, but also achieve high responsiveness to complete automatic testing and eliminate the randomness of test results.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0008] A multi-threaded motor startup monitoring and protection automatic calibration algorithm, a relay protection device based on motor startup detection, a relay protection tester for simulating secondary side faults in a substation, and an external computer installed with a Windows system, characterized by the following steps:

[0009] S1: Closed-loop test system connection: First, connect the current output port of the relay protection tester to the phase current CT terminal in the cabinet that connects to the relay protection device with a test wire; then connect the switch input port of the relay protection tester to the outlet node of the startup monitoring unit of the relay protection device with a test wire, and connect the control interfaces of the startup monitoring units of the relay protection tester and the relay protection device to the external computer to form a test closed-loop network;

[0010] S2: Startup monitoring unit status parameter setting: Verify and modify the setting list of the protection unit to be tested and its status control registers SG4 and SGF / 7;

[0011] S3: Tester output excitation control: The relay protection tester automatically adjusts the output excitation of the relay protection tester by analyzing and processing the protection side parameter configuration read by the external computer, so as to automatically calibrate the startup monitoring protection action time; the automatic calibration automatically blocks each test process by adding a thread lock, and releases the thread lock after the flag bit of the calibration procedure is verified to realize the advancement of the test process, and at the same time publishes a sub-thread to control other system objects.

[0012] Preferably, the relay protection tester uses an Ethernet ENC28J60 model chip. In step S1, the relay protection tester is connected to the external computer for communication control based on the TCP / IP transmission control protocol through an independent Ethernet controller with an industry-standard serial peripheral interface carried by the Ethernet ENC28J60 model chip.

[0013] Preferably, the startup monitoring unit of the relay protection device uses a CH340T level conversion chip. In step S1, the startup monitoring unit is connected to the external computer through a DB-9 specification connector connected to the RS-232 standard interface carried by the CH340T level conversion chip; the signal content of each pin of the DB-9 specification connector is specified.

[0014] Preferably, the relay protection tester includes eight pairs of electrical isolation input signals, which can isolate 500V voltage, and can be connected to empty nodes and 0-250V potential-carrying nodes; the input signal common terminal controls internal connection and disconnection; the software-controllable anti-shake time is 0-20s; A, B, and C on the relay protection tester are respectively connected to the trip A, trip B, and trip C contacts of the protection, and R is connected to the reclosing contact of the protection. The response time is within 100 μs, and instantaneous capture of the protection action signal can be achieved.

[0015] Preferably, the start monitoring unit includes an input current Is / In setting value register, an action time Ts setting value register, an element action indication register, a thermal stress monitoring soft switch SGF / 7, and an SG4 / 1 for selecting the protection export action condition.

[0016] Preferably, in step S2, by setting the thermal stress monitoring soft switches SGF / 7 and SG4 / 1, the input current Is can be set as the actual starting current of the motor and the time Ts can be set as the normal starting time of the motor; after the relay protection device completes sampling, calculate Is 2 The product of the time Ts, and the result is regarded as the thermal stress accumulated during the normal starting of the motor. When the starting current Is exceeds the set value, the start monitoring unit starts to calculate the thermal stress accumulation value. When it exceeds the theoretical thermal stress of the motor starting, the protection trip export unit acts, and the action signal is sent from the element action indication register to the external computer.

[0017] Preferably, the protection-side parameter configuration in step S3 includes at least the amplitude, frequency, phase control of the tester voltage and current, as well as the action value, return value, action time information acquisition, automatic verification of test results, data upload, and device reset of the tester input signals.

[0018] Preferably, the test process in step S3 is based on an operating system thread pool built between the relay protection device, the relay protection tester, and the external computer. The operating system thread pool includes the main thread on the external computer side and the sub-threads on the relay protection device and relay protection tester sides; the test process is a test process under a single setting value, which is set between the main thread and the sub-threads and is respectively connected to the output end of the sub-thread and the input end of the main thread through a thread lock.

[0019] Due to the adoption of the above technical solutions, the technical progress achieved by the present invention is as follows.

[0020] The present invention has high test reliability: compared with traditional manual testing, the external computer is used as the main control of the verification system, and device scheduling is based on a multi-thread mechanism, meeting the safety requirements of relay protection regulations.

[0021] High test efficiency: Based on the closed-loop test system, it can synchronously control the relay protection tester and the relay protection device according to the motor protection verification regulations. There is no need to manually modify the device setting values and status parameters, and it can complete automatic tests with high responsiveness.

[0022] Complete test data volume: The excitation output by the relay protection tester is used to collect the status parameters of the relay protection device in real time through an external computer for self-adjustment. It replaces single-point manual testing with high-bandwidth interval testing to eliminate the randomness of test results.

[0023] Low cost and wide application range: To build a closed-loop test system, only protocol support is required for communication. Compared with the original microcomputer relay protection tester test, except for wiring adjustments, no additional hardware devices need to be added. Description of the drawings

[0024] Figure 1 is the technical roadmap of the present invention;

[0025] Figure 2 is the network port protocol control loop diagram of the relay protection tester of the present invention;

[0026] Figure 3 is the serial port protocol control loop diagram of the start monitoring unit of the present invention;

[0027] Figure 4 is the wiring diagram of the digital input port of the relay protection tester of the present invention and the outlet node of the start monitoring unit of the relay protection device;

[0028] Figure 5 is the closed-loop system diagram of the protection automatic test of the present invention;

[0029] Figure 6 is the control register group diagram of the start monitoring unit of the present invention;

[0030] Figure 7 is the diagram of the programmed output excitation change of the relay protection tester of the present invention;

[0031] Figure 8 is the flowchart of the start monitoring protection automatic test of the present invention. Detailed implementation manners

[0032] The present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0033] An automatic calibration algorithm for motor start monitoring and protection based on multi-threading, in combination with Figure 1 As shown, it includes three main stages, namely: S1: Connection of the closed-loop test system, S2: Setting of the status parameters of the start monitoring unit, and S3: Control of the tester output excitation. The specific content of each stage is as follows:

[0034] S1: Closed-loop test system connection. First, use test wires to connect the current output port of the relay protection tester to the phase current CT terminal in the cabinet that is connected to the relay protection device. Then, use test wires to connect the digital input port of the relay protection tester to the outlet node of the startup monitoring unit of the relay protection device, and connect the control interfaces of the relay protection tester and the startup monitoring unit of the relay protection device to an external computer to form a test closed-loop network.

[0035] According to the secondary drawing, use test wires to connect the current output port of the relay protection tester to the phase current CT terminal in the cabinet that is connected to the relay protection device. The secondary drawing is the connection relationship diagram between the relay protection tester interface and the secondary side of the power grid.

[0036] S2: State parameter setting of the startup monitoring unit. Verify and modify the setting list of the protection unit to be tested and its status control registers SG4 and SGF / 7. If the value of SGF / 7 is 1, it indicates that the startup monitoring protection is based on thermal stress monitoring; otherwise, it indicates that the startup monitoring protection is based on definite-time overcurrent protection.

[0037] The protection unit to be tested depends on the wiring of the relay protection device and the register value of the relay protection device.

[0038] S3: Tester output excitation control. The relay protection tester analyzes and processes the protection-side parameter configuration read by the external computer, and automatically adjusts the output excitation of the relay protection tester, including the amplitude, frequency, and phase control of the tester voltage and current, as well as the acquisition of the action value, return value, and action time information of the tester input, automatic verification of the test results, data upload, and device reset, so as to automatically verify the action time of the startup monitoring protection.

[0039] The design scheme of the relay protection automatic test system adopted by the present invention is as Figures 2 to 5 shown.

[0040] Figure 5 It is a diagram of the protection automatic test closed-loop system. The hardware device is mainly divided into three parts, including a relay protection device for motor startup detection, a relay protection tester for simulating secondary side faults of a substation, and an external computer installed with a Windows system.

[0041] Figure 2It is the network port protocol control circuit diagram of the relay protection tester. It uses the ENC28J60 model chip of Ethernet, which is an independent Ethernet controller with an industry-standard Serial Peripheral Interface (SPI). It conducts communication control based on the TCP / IP transmission control protocol. Its principle is that the application process in the source host first delivers the data to the application layer. The application layer adds the necessary control information to form a message stream and passes it down to the transport layer. The transport layer adds the control information of this layer to the received data unit to form a segment or datagram and then passes it to the internet layer. The internet layer adds the control information of this layer to form an IP datagram and passes it to the network interface layer. The network interface layer assembles the IP datagram handed down by the internet layer into a frame and transmits it to the network hardware (i.e., the physical layer) in the form of a bit stream, and the data is sent to the destination host.

[0042] Figure 3 It is the serial port protocol control circuit diagram of the start monitoring unit. It uses the RS-232 standard interface for connection and the DB-9 specification connector. Based on the CH340T level conversion chip in the protocol, the signal content of each pin of the connector is specified.

[0043] Figure 4 It is the wiring diagram of the digital input port of the relay protection tester and the outlet node of the start monitoring unit of the relay protection device. The relay protection tester includes eight pairs of electrical isolation inputs, which can isolate 500V voltage and can connect to empty nodes and nodes with potential (0 - 250V); the common terminal of the inputs controls the internal connection and disconnection; the software-controllable anti-shake time: 0 - 20s; A, B, and C on the relay protection tester are respectively connected to the trip A, trip B, and trip C contacts of the protection, and R is connected to the reclosing contact of the protection; its response time is within 100μs, and it can instantaneously capture the protection action signal.

[0044] The setting principle of the start monitoring protection unit adopted by the present invention is as follows:

[0045] Figure 6 It is the control register group diagram of the start monitoring unit, including the setting value register of the start monitoring Is / In (input current), the setting value register of the start monitoring Ts (action time), the element action indication register, the thermal stress monitoring soft switches SGF / 7 and SG4 / 1 to select the protection outlet action conditions. SG4 / 1 is a bit in the SG4 register, and its value determines the start monitoring current calculation mode. To ensure the integrity of the setting values, all setting values are recorded in two independent memory banks in the permanent memory of the relay protection device, and each memory bank uses a checksum to verify its stored content.

[0046] When the relay protection device is in normal operation, if the content of a set of memory banks is damaged due to some reason, the entire set of setting values of the relay protection device will be extracted from another set of memory banks and transmitted to the faulty storage area. If both sets of memory banks are damaged, the relay will exit the working state, and an alarm signal will be sent through the serial port and the IRF (internal fault) output relay to start monitoring with the rated starting current Is 2 in the form of the product of time Ts as the basis for action.

[0047] By setting the thermal stress monitoring soft switches SGF / 7 and SG4 / 1, the input current Is can be set to the actual starting current of the motor, and the time Ts can be set to the normal starting time of the motor. After the relay protection device completes sampling, calculate Is 2 and the product of time Ts. The result is regarded as the thermal stress accumulated during the normal starting of the motor. When the starting current Is exceeds the set value, the starting monitoring unit starts to calculate the thermal stress accumulation value. When it exceeds the theoretical thermal stress of the motor starting, the protection tripping output unit acts, and the action signal is sent from the component action indication register to the system host. This form of motor starting monitoring can ensure that under low voltage conditions, the allowable starting time is extended to the maximum thermal stress of the motor set by the set value.

[0048] The output excitation change process and control method adopted by the tester of the present invention are as follows:

[0049] The relay protection device is incorporated into the communication closed-loop network in the automatic calibration procedure, and the status parameters of the calibration object can be monitored according to the calibration needs at the software level, such as the current three-phase input excitation value, the current thermal level of the starting monitoring unit, the starting / locking status of each component of the comprehensive protection, and the protection starting / tripping status quantity, etc. And in different test stages, the relay protection tester is made to complete the simulation of the fault state, such as Figure 7 shown. The simulation process needs to regulate parameters including the starting point of the output excitation change, the fault simulation time, the time interval before the fault, the magnitude of the voltage and current before and after the fault in each stage, and the magnitude of the change end value, and remotely change the setting value of the protection device and restore the status through the message. Thus, real-time control of the calibration object is realized based on the communication network, enabling it to participate in the calibration procedure to cooperate in completing the test process.

[0050] Such as Figure 8As shown, the comprehensive protection verification procedure has a distinct execution order in logical steps and has extremely high requirements for the standardization and reliability of each operation. For this, an operating system thread pool is constructed among the relay protection device, the relay protection tester, and the external computer. The operating system thread pool includes the main thread on the external computer side and the sub-threads on the relay protection device and the relay protection tester side; and by adding thread locks, each test process is automatically blocked. The test process is the test process under a single setting value, which is set between the main thread and the sub-threads and is respectively connected to the output end of the sub-thread and the input end of the main thread through thread locks. After the flag bit verification of the verification procedure passes, the thread lock is released to realize the advancement of the test process, and at the same time, the sub-thread is released to control other system objects.

[0051] Among them, the leftmost is the main thread. To ensure real-time performance, it is only responsible for receiving the verification parameters and alarm information returned by the listening thread and updating the status of the external computer UI form to ensure the highest-priority control right of the tester over the verification operation.

[0052] In the middle is the test process under a single setting value, which is responsible for the main logic control of the verification operation. After each step of the verification operation is issued, it applies for the operation to be executed by the sub-thread response from the operating system thread pool and locks itself automatically. After the sub-thread callback function finishes executing, it verifies the operation execution result identifier, and only continues to execute after the verification passes, ensuring the safety of the test process and avoiding potential safety hazards caused by hardware failures.

[0053] After obtaining the test result, the excitation output by the relay protection tester, the status parameters of the starting monitoring unit, and the setting value are automatically restored, the thread pool is cleared, and the test ends after the test result is output on the external computer UI form.

Claims

1. An automatic calibration algorithm for motor startup monitoring and protection based on multi-threading, a relay protection device for motor startup detection, a relay protection tester for simulating secondary side faults of a substation, and an external computer installed with a Windows system, characterized in that: It includes the following steps: S1: Closed-loop test system connection: First, connect the current output port of the relay protection tester to the phase current CT terminal in the cabinet that connects to the relay protection device with test leads; then connect the digital input port of the relay protection tester to the outlet node of the start monitoring unit of the relay protection device with test leads, and connect the control interfaces of the relay protection tester and the start monitoring unit of the relay protection device to an external computer to form a test closed-loop network; S2: Setting of the status parameters of the start monitoring unit: Verify and modify the setting sheet of the protection unit to be tested and its status control registers SG4 and SGF / 7; The start monitoring unit includes an input current Is / In setting register, an operation time Ts setting register, an element operation indication register, a thermal stress monitoring soft switch SGF / 7, and SG4 / 1 to select the protection outlet action condition; In step S2, by setting the thermal stress monitoring soft switches SGF / 7 and SG4 / 1, the input current Is can be set to the actual starting current of the motor and the time Ts can be set to the normal starting time of the motor; After the relay protection device completes sampling, calculate the product of Is2 and the time Ts, and the result is regarded as the thermal stress accumulated during the normal starting of the motor. When the starting current Is exceeds the set value, the start monitoring unit starts to calculate the thermal stress accumulation value. When it exceeds the theoretical thermal stress of the motor starting, the protection trip outlet unit acts, and the action signal is sent from the element operation indication register to the external computer; S3: Tester output excitation control: The relay protection tester automatically adjusts the output excitation of the relay protection tester by analyzing and processing the protection-side parameter configuration of the relay protection device read by the external computer, so as to automatically verify the action time of the start monitoring protection; the automatic verification automatically blocks each step of the test process by adding a thread lock, and releases the thread lock after the flag bit of the verification procedure is verified to advance the test process, and at the same time publishes a child thread to control other system objects; The test process in step S3 is based on an operating system thread pool built between the relay protection device, the relay protection tester, and the external computer. The operating system thread pool includes a main thread on the external computer side, child threads on the relay protection device and relay protection tester sides, and a listening thread connected between the main thread and the child threads; the test process is a test process under a single setting value, which is set between the main thread and the child threads and is respectively connected to the output end of the child thread and the input end of the main thread through a thread lock.

2. The automatic verification algorithm for motor starting monitoring and protection based on multi-threading according to claim 1, wherein: The relay protection tester uses an Ethernet ENC28J60 model chip. In step S1, the relay protection tester is connected to the external computer for communication control based on the TCP / IP transmission control protocol through an independent Ethernet controller with an industry-standard serial peripheral interface carried by the Ethernet ENC28J60 model chip.

3. The automatic verification algorithm for motor startup monitoring and protection based on multi-threading according to claim 1, wherein: The startup monitoring unit of the relay protection device uses a CH340T level conversion chip. In step S1, the startup monitoring unit is connected to an external computer through a DB-9 specification connector connected to the RS-232 standard interface of the CH340T level conversion chip; the signal content of each pin of the DB-9 specification connector is specified.

4. The automatic calibration algorithm for motor startup monitoring and protection based on multi-threads according to claim 1, characterized in that: The relay protection tester includes eight pairs of electrical isolation inputs, which can isolate 500V voltage, and can connect to empty nodes and 0~250V potential-carrying nodes; the common terminal of the inputs controls the internal connection and disconnection; the software-controlled anti-shake time is 0~20s; A, B, and C on the relay protection tester are respectively connected to the trip A, trip B, and trip C contacts of the protection, and R is connected to the reclosing contact of the protection. The response time is within 100μs, and the protection action signal can be instantaneously captured.

5. An automatic verification algorithm for motor startup monitoring and protection based on multi-threading according to claim 1, characterized in that: The protection-side parameter configuration in step S3 includes at least the amplitude, frequency, and phase control of the tester voltage and current, as well as the acquisition of the action value, return value, and action time information of the tester inputs, automatic verification of test results, data upload, and device reset.

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