A test device for a thyristor control unit of a converter valve

Abstract

The application relates to the field of direct current transmission, in particular to a thyristor control unit testing device of a converter valve, which comprises a main control module, a pulse timing module, an analog impulse voltage module and a sampling module; the analog impulse voltage module is connected with the main control module, so as to generate an impulse voltage according to the instruction of the main control module, and is used for connecting the measured thyristor control unit, so as to transmit the generated impulse voltage to the measured thyristor control unit and test the protection triggering function of the measured thyristor control unit; the analog impulse voltage module comprises an energy storage capacitor and an inductor, the energy storage capacitor is used for being connected in series with a power supply, and the inductor is connected in series at the output end of the capacitor, so as to output the impulse voltage; the main control module is used for sending an instruction to the analog impulse voltage module according to the voltage of the energy storage capacitor, and is also used for judging the test result of the protection triggering function of the measured thyristor control unit according to the received signal. The device is favorable for the debugging and analysis of the thyristor control unit.

Description

Technical Field

[0001] This invention relates to a test device for a converter valve thyristor control unit, belonging to the field of DC power transmission. Background Technology

[0002] The thyristor control unit is a key component of the converter valve assembly in DC transmission projects. It serves as a communication bridge between the valve control equipment and the thyristor stage, monitoring the voltage status of the thyristor stage and possessing functions such as energy harvesting and sampling, thyristor triggering, forward protection triggering, and reverse recovery period protection triggering. Before assembling the converter valve assembly, routine tests on the thyristor control unit only tested its energy harvesting and low-voltage triggering functions, lacking verification and debugging methods for its low-voltage protection triggering function. Summary of the Invention

[0003] The purpose of this invention is to provide a test device for the thyristor control unit of a converter valve, so as to solve the problem of lack of low-pressure simulation protective trigger test in the testing of the converter valve control unit.

[0004] To achieve the above objectives, the present invention includes:

[0005] This invention provides a testing device for a converter valve thyristor control unit, comprising a main control module, a pulse timing module, a simulated impulse voltage module, and a sampling module;

[0006] The pulse timing module is connected to the main control module and is used to generate corresponding synchronization signals and test pulse timings for different thyristor control units under test.

[0007] The simulated impulse voltage module is connected to the main control module to generate impulse voltage according to the instructions of the main control module. It is also used to connect to the control unit of the thyristor under test to transmit the generated impulse voltage to the control unit of the thyristor under test and test the protection triggering function of the control unit of the thyristor under test. The simulated impulse voltage module includes an energy storage capacitor and an inductor. The energy storage capacitor is connected in series with the power supply, and the inductor is connected in series with the output terminal of the capacitor to output the impulse voltage.

[0008] The sampling module is used to collect the voltage of the energy storage capacitor, and is also used to connect to the control unit of the thyristor under test to collect the internal signals of the control unit. It is also connected to the main control module to send the collected signals to the main control module.

[0009] The main control module is used to send commands to the simulated impulse voltage module based on the voltage of the energy storage capacitor, and also to judge the test results of the protection trigger function of the thyristor control unit under test based on the received signals.

[0010] Beneficial effects: The present invention provides a test device for a converter valve thyristor control unit, including a main control module, a pulse timing module, a simulated impulse voltage module, and a sampling module. The sampling module acquires the sampling signal and sends the signal to the main control module. The main control module controls the simulated impulse voltage module to generate an impulse voltage based on the received signal. The impulse voltage is then input to the thyristor control unit under test to trigger the corresponding protection function, thereby realizing the test of the protection function.

[0011] Furthermore, the simulated impulse voltage module also includes a delay circuit for changing the magnitude of the generated impulse voltage wavefront. The delay circuit includes a first resistor and a delay capacitor connected in series, and is used in parallel with the control unit of the thyristor under test.

[0012] Beneficial effect: By setting the delay circuit, the control of small signal impulse voltage is achieved.

[0013] Furthermore, the simulated impulse voltage module also includes a discharge circuit for discharging the energy storage capacitor, the discharge circuit including a second resistor connected in parallel with the energy storage capacitor.

[0014] Beneficial effect: By setting up the discharge circuit, the energy of the energy storage capacitor is discharged.

[0015] Furthermore, the testing device also includes a photoelectric conversion module, which includes a light receiving unit and a comparator. One end of the light receiving unit is connected to the control unit of the thyristor under test to receive the light signal emitted by the control unit and perform photoelectric conversion. The other end is connected to the non-inverting input of the comparator. The inverting input of the comparator is connected to the threshold setting, and the output of the comparator is connected to the main control module.

[0016] The main control module is also used to determine whether the optical output function of the thyristor control unit under test is normal based on the output of the comparator.

[0017] Beneficial effects: The photoelectric conversion module can convert light signals into electrical signals. The comparator can compare the input value with the set threshold value, and the output of the comparator can be used to determine whether the light output function of the thyristor control unit under test is normal.

[0018] Furthermore, the photoelectric conversion module also includes a voltage follower and a light emitting unit. The non-inverting input of the voltage follower is connected to a voltage signal, and the output is connected to one end of the light emitting unit to perform electro-optical conversion. The other end of the light emitting unit is used to connect to the control unit of the thyristor under test.

[0019] Beneficial effects: The optical emission module can convert electrical signals into optical signals, and the optical power of the emitted optical signal can be adjusted by the follower.

[0020] Furthermore, it also includes a host computer, which is connected to the main control module and is used to send test modes to the main control module; it is also connected to the non-inverting input of the comparator and the non-inverting input of the voltage follower in the photoelectric conversion module, so as to output the setting threshold and the voltage signal respectively.

[0021] Beneficial effects: Different test modes for thyristors can be set via the host computer, and different pulse control timing electrical signals can be generated via the pulse timing module.

[0022] Furthermore, the pulse timing module includes a differential input circuit, a conditioning circuit, a reference voltage circuit, and several comparator circuits. The output of the differential input circuit is connected to the input of the conditioning circuit. Each comparator circuit includes a comparator. The output of the conditioning circuit is connected to the non-inverting input of the comparator. The reference voltage circuit is connected to the inverting input of the comparator. The output of each comparator is used to output the timing of each test pulse.

[0023] Beneficial effect: The timing of each test pulse can be obtained through the output of each comparator in the pulse timing module.

[0024] Furthermore, the protection of the thyristor control unit under test includes BOD protection and DUDT protection, and is used to test BOD protection when the delay circuit is connected to the test device, and to test DUDT protection when the delay circuit is not connected to the test device.

[0025] Beneficial effects: When the delay circuit is connected to the test device, it is used to test the BOD protection; when the delay circuit is not connected to the test device, it is used to test the DUDT protection, thus completing the BOD protection and DUDT protection of the thyristor control unit under test.

[0026] Furthermore, the testing device also includes a drive circuit module, and the main control module is connected to the simulated impulse voltage module through the drive circuit module to control the switching devices of the simulated impulse voltage module to be turned on or off.

[0027] Beneficial effects: The driving circuit enables control of each switching transistor in the simulated impulse voltage, ensuring the timing of the test pulse control switches and thus guaranteeing the test. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the test device for the converter valve thyristor control unit of the present invention;

[0029] Figure 2 This is a schematic diagram of the analog voltage module of the present invention;

[0030] Figure 3 This is a schematic diagram of the photoelectric conversion module of the present invention;

[0031] Figure 4 This is a flowchart of the test method for the converter valve thyristor control unit of the present invention;

[0032] Figure 5 This is a schematic diagram of the differential input circuit and conditioning circuit of the present invention;

[0033] Figure 6 This is a schematic diagram of the comparator circuit of the present invention;

[0034] Figure 7 This is a schematic diagram of the sampling module circuit of the present invention. Detailed Implementation

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0036] The converter valve thyristor control unit testing device provided by this invention is as follows: Figure 1 As shown, this testing device can test the power harvesting, triggering and feedback functions, as well as the protective triggering functions of the converter valve thyristor control unit, and is compatible with the functional verification of various types of converter valve thyristor control units. The testing device includes a main control module, an upper control unit, a pulse timing module, a drive circuit module, a simulated impulse voltage module, a sampling module, and a photoelectric conversion module. For different types of thyristor control units, by setting different pulse control timing sequences and using a simulated impulse voltage circuit, the switching and adjustable devices in the circuit are controlled. A simulated impulse voltage with controllable wavefront and peak is generated using a power frequency power supply to test the forward protection triggering and reverse recovery period protection triggering functions of the converter valve thyristor control unit.

[0037] The host computer is connected to the main control module and is used to send test modes to the main control module. It is also connected to the non-inverting input of the comparator and the non-inverting input of the voltage follower in the photoelectric conversion module through the analog-to-digital converter U2 in the photoelectric conversion module, so as to output the setting threshold and voltage signal respectively.

[0038] The pulse timing module is primarily designed for different types of thyristor control units, generating corresponding synchronization signals and test pulse timing sequences. The pulse timing module, for example... Figure 5 and Figure 6 As shown, it consists of a differential input circuit, a conditioning circuit, a reference voltage circuit, and five comparator circuits. The output of the differential input circuit is connected to the input of the conditioning circuit. Each comparator circuit includes a comparator. The output of the conditioning circuit is connected to the non-inverting input of the comparator. The reference voltage circuit is connected to the inverting input of the comparator. Each comparator can generate synchronization signals FCS1-FCS5 to generate test pulse timing. The test pulses are generated using the power frequency power supply, and the electrical signal controlling the pulse timing is converted into an optical signal through a photoelectric conversion circuit, which interacts with the thyristor control unit.

[0039] Sampling module such as Figure 5 and Figure 7 As shown, the system consists of a differential amplifier circuit, a conditioning circuit, and a high-speed analog-to-digital converter, enabling high-precision sampling of electrical signals at a sampling rate in the megahertz range. The sampling module is connected to the thyristor control unit to sample the internal signals of the thyristor control unit, detecting whether its power extraction, triggering, and feedback functions are normal. It is also connected to the energy storage capacitor in the analog pulse voltage module to measure the charging voltage of the energy storage capacitor in real time; charging of the energy storage capacitor stops when the charging voltage exceeds a preset value.

[0040] The drive circuit module consists of a high-speed isolation chip and transistors. The drive circuit module is connected to the main control module, and the main control module is connected to the analog impulse voltage module through the drive circuit module. It is used in conjunction with the test pulse timing to control the switching devices of the analog impulse voltage module to turn on or off.

[0041] The main control module is used to send commands to the simulated impulse voltage module based on the voltage of the energy storage capacitor. It is also used to judge the test results of the protection trigger function of the thyristor control unit under test based on the received signals. The main control module controls the optical power threshold of the received and emitted signals through the bus. The optical power threshold is set by the host computer.

[0042] The simulated impulse voltage module can output a small-signal impulse voltage for protective triggering tests of thyristor control units, including BOD trigger tests and DUDT trigger tests. The wavefront of the DUDT trigger test differs significantly from that of the BOD trigger test. Figure 2 As shown, the simulated impulse voltage module comprises switching devices T1~T4, an energy storage capacitor C1, an inductor L1, a third resistor R1, a second resistor R2, a first resistor R3, and a delay capacitor C2. T1 is connected in series with the third resistor R1 and the energy storage capacitor; switching device T1 controls the charging of the energy storage capacitor. The energy storage capacitor C1, switching devices T2 and T4, and the second resistor R2, connected in series, form a discharge circuit for discharging the energy storage capacitor. The switching device T3, the first resistor R3, and the delay capacitor C2, connected in series, form a delay circuit for adjusting the small-signal impulse voltage wavefront.

[0043] The switching devices are controlled by the main control module through the drive circuit module, and the switching of devices T1~T4 is controllable. When T1 is on, charging of the energy storage capacitor C1 begins. The sampling module measures the charging voltage of the energy storage capacitor in real time. When the charging voltage exceeds the preset value, charging stops, i.e., T1 is turned off and T2 is turned on. The energy storage capacitor C1 outputs a control voltage signal to the thyristor control unit. Changing the set value of the voltage at the terminal of the energy storage capacitor C1 can change the peak value of the control voltage signal. Changing the inductance value of L1 can adjust the wavefront. When T4 is on, the energy storage capacitor C1 discharges through the second resistor R2 to release the charge in the energy storage capacitor C1. When T3 is on, the delay circuit composed of the delay capacitor C2 and the first resistor R3 is turned on, and the wavefront of the control voltage signal will be significantly reduced. The wavefront can be adjusted by adjusting the adjustable first resistor R3. By adjusting the parameters of the energy storage capacitor C1, the delay capacitor C2, the inductor L1, and the third resistor R3, the wavefront of the control voltage signal can be adjusted. When T3 is open, it is used to trigger the DUDT protection test of the thyristor control unit. When T3 is closed, it is used to trigger the BOD protection test of the thyristor control unit.

[0044] The photoelectric conversion module can output and receive optical signals of different power and type, used to detect whether the optical signal transmission and reception function of the thyristor control unit is normal. For example... Figure 3 As shown, the photoelectric conversion module includes an analog-to-digital converter (ADC) U2, a comparator U3, a light receiver, a light emitter, and a voltage follower U4. The host computer is connected to the ADC U2 via a bus. One end of the light receiver is connected to the control unit of the thyristor under test, and the other end is connected to the non-inverting input of the comparator. The output of the comparator is connected to the main control module. The light receiver converts the optical signal into an electrical signal, which is then compared with a set threshold (i.e., the first output of the ADC U2) connected to the inverting input of the comparator. The output result is transmitted to the main control module. The non-inverting input of the voltage follower is connected to the second output of the ADC U2, and its output is connected to one end of the light emitter unit. The other end of the light emitter unit is used to connect to the control unit of the thyristor under test.

[0045] The optical receiver converts optical signals into electrical signals, while the optical transmitter converts electrical signals back into optical signals. Within the operating range of the optical devices, the drive current and optical power are positively correlated. Furthermore, a comparator processes the output level of the analog-to-digital converter (ADC) to change the drive current of the optical devices, thus setting the optical power threshold. The ADC converts bus information into level signals, enabling the host computer to set the optical power threshold in real time. The main control module controls the output level of the ADC U2 via the bus and uses comparator U3 to set the optical power threshold of the optical receiver module U1. When the optical power exceeds the threshold, the information is uploaded to the main control module. A voltage follower U4 changes the drive current of the optical transmitter module U5 to adjust the optical power of the transmitted optical signal. The optical receiver module of the photoelectric conversion module is connected to the optical transmitter module of the thyristor control unit to determine if the thyristor control unit's optical transmitter module is functioning correctly. The optical transmitter module of the photoelectric conversion module is also connected to the optical receiver module of the thyristor control unit to verify if the thyristor control unit's optical receiver module is functioning correctly, thereby verifying the functionality of the thyristor control unit's optical module. The verification process is as follows: the optical transmitter module U5 in the photoelectric conversion module transmits an optical signal to the thyristor control unit. After the optical receiver module in the thyristor control unit receives the optical signal, it will transmit the optical signal to the optical receiver module U1 of the photoelectric conversion module through the optical transmitter module of the thyristor control unit. Then, the comparator U3 outputs the signal IN to the main control module. The main control module determines whether the optical function of the thyristor control unit is normal based on the magnitude of the signal IN.

[0046] The flowchart of the test method for the converter valve thyristor control unit is as follows: Figure 4 As shown,

[0047] Step 1: For different types of thyristor control units, preset the test mode, preset the test pulse timing and parameter values.

[0048] Step 2: Obtain the output power voltage through the thyristor control unit test device, sample the voltage of the thyristor control unit, and determine whether the power extraction function is normal. If it is normal, verify other functions; if it is not normal, stop.

[0049] Step 3: Obtain the energy extraction voltage through the thyristor control unit test device, sample the voltage of the thyristor control unit, and trigger a pulse to determine whether the triggering and return check are normal. If normal, verify other functions; if abnormal, stop.

[0050] Step 4: The thyristor control unit test device adjusts the optical power threshold of the photoelectric conversion module and performs a trigger test to determine whether the optical module is normal. If it is normal, other functions are verified; if it is not normal, the test is stopped.

[0051] Step 5: Simulate the impulse voltage to enter the BOD detection mode. The thyristor control unit test device outputs the energy harvesting voltage, sampling voltage, and impulse voltage, and generates trigger pulses. The thyristor control unit emits corresponding light signals in the corresponding pulse timing sequence to indicate that the protection has been triggered to test. Determine whether the BOD protection is normal: if it is normal, then verify other functions; if it is not normal, then stop.

[0052] Step 6: Simulate the impulse voltage to enter the DUDT detection mode. The thyristor control unit test device outputs the energy harvesting voltage, sampling voltage, and impulse voltage, and triggers a pulse to determine whether the DUDT protection is normal. If it is normal, the test process ends; if it is not normal, the test process also ends.

[0053] The above steps have completed the comprehensive verification of the thyristor control unit's functionality.

[0054] The testing device of this invention provides a simulated impulse voltage module capable of generating small-signal impulse voltages with adjustable wavefronts and peaks. A testing method and apparatus for the thyristor control unit of a converter valve are designed to test the power harvesting function, triggering and feedback functions of the thyristor control unit, and verify its BOD protection and reverse recovery period protection functions, which is beneficial for the debugging and analysis of the thyristor control unit. The thyristor control unit testing device can perform comprehensive functional testing of the thyristor control unit. The functional modules of the testing device are integrated on a single board, presenting a portable device compatible with various types of thyristor control units, thus improving the safety and efficiency of functional testing of the converter valve thyristor control unit.

Claims

1. A testing device for a converter valve thyristor control unit, characterized in that, It includes a main control module, a pulse timing module, an analog impulse voltage module, and a sampling module; The pulse timing module is connected to the main control module and is used to generate corresponding synchronization signals and test pulse timings for different thyristor control units under test. The pulse timing module includes a differential input circuit, a conditioning circuit, a reference voltage circuit, and a comparator circuit. The output of the differential input circuit is connected to the input of the conditioning circuit. Each comparator circuit includes a comparator. The output of the conditioning circuit is connected to the non-inverting input of the comparator. The reference voltage circuit is connected to the inverting input of the comparator. The output of each comparator is used to output the timing of each test pulse. The conditioning circuit includes a conditioning comparator. The non-inverting input of the conditioning comparator is connected to the output of the differential input circuit. The inverting input is grounded through a first resistor. The output is connected to the inverting input through a second resistor. The output is also grounded through two Schottky diodes connected in reverse series. The simulated impulse voltage module is connected to the main control module to generate impulse voltage according to the instructions of the main control module. It is also used to connect to the control unit of the thyristor under test to transmit the generated impulse voltage to the control unit of the thyristor under test and test the protection triggering function of the control unit of the thyristor under test. The simulated impulse voltage module includes an energy storage capacitor and an inductor. The energy storage capacitor is connected in series with the power supply, and the inductor is connected in series with the output terminal of the capacitor to output the impulse voltage. The sampling module is used to collect the voltage of the energy storage capacitor, and is also used to connect to the control unit of the thyristor under test to collect the internal signals of the control unit. It is also connected to the main control module to send the collected signals to the main control module. The main control module is used to send commands to the simulated impulse voltage module based on the voltage of the energy storage capacitor, and also to judge the test results of the protection trigger function of the thyristor control unit under test based on the received signals.

2. The test device for the converter valve thyristor control unit according to claim 1, characterized in that, The simulated impulse voltage module also includes a delay circuit for changing the magnitude of the generated impulse voltage wavefront. The delay circuit includes a first resistor and a delay capacitor connected in series. The delay circuit is used to connect in parallel with the control unit of the thyristor under test.

3. The test device for the converter valve thyristor control unit according to claim 1, characterized in that, The simulated impulse voltage module also includes a discharge circuit for discharging the charge of the energy storage capacitor, the discharge circuit including a second resistor connected in parallel with the energy storage capacitor.

4. The test device for the converter valve thyristor control unit according to claim 1, characterized in that, The testing device also includes a photoelectric conversion module, which includes a light receiving unit and a comparator. One end of the light receiving unit is connected to the control unit of the thyristor under test to receive the light signal emitted by the control unit and perform photoelectric conversion. The other end is connected to the non-inverting input of the comparator. The inverting input of the comparator is connected to the threshold setting. The output of the comparator is connected to the main control module. The main control module is also used to determine whether the optical output function of the thyristor control unit under test is normal based on the output of the comparator.

5. The test device for the converter valve thyristor control unit according to claim 4, characterized in that, The photoelectric conversion module also includes a voltage follower and a light emitting unit. The in-phase input terminal of the voltage follower is connected to a voltage signal, and the output terminal is connected to one end of the light emitting unit to perform electro-optical conversion. The other end of the light emitting unit is used to connect to the control unit of the thyristor under test.

6. The test device for the converter valve thyristor control unit according to claim 5, characterized in that, It also includes a host computer, which is connected to the main control module and is used to send the test mode to the main control module; it is also connected to the non-inverting input of the comparator and the non-inverting input of the voltage follower in the photoelectric conversion module, so as to output the set threshold and the voltage signal respectively.

7. The test device for the converter valve thyristor control unit according to claim 2, characterized in that, The protection of the thyristor control unit under test includes BOD protection and DUDT protection. When the delay circuit is connected to the test device, it is used to test the BOD protection, and when the delay circuit is not connected to the test device, it is used to test the DUDT protection.

8. The test device for the converter valve thyristor control unit according to claim 1, characterized in that, The testing device also includes a drive circuit module, and the main control module is connected to the simulated impulse voltage module through the drive circuit module to control the switching devices of the simulated impulse voltage module to turn on or off.

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