Method for testing high-voltage direct-current transmission phase selection closing device through large resistor
Through the combination of a transient high current generator and a large resistor, the phase angle of the phase selection and closing device is collected in real time, solving the problem of low test accuracy in the prior art and achieving higher accuracy and reliability.
Patent Information
- Application Number
- CN202411760384.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-03-14
AI Technical Summary
The prior art cannot accurately capture the moment of the phase selection and closing device, resulting in low accuracy of its test results.
The excitation is provided through a transient high current generator, and the large resistor is used to connect it in parallel with the circuit breaker and the current transformer, combined with the relay protection tester and the wireless voltage phase reference source, to collect and judge the phase angle accuracy of the phase selection and closing device in real time.
The accuracy of the phase-selecting and closing verification method is improved, the testing accuracy of the phase-selecting and closing device is enhanced, and the control accuracy and reliability of the device are ensured.
Smart Images
Figure CN119619820A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of power system automation, and in particular relates to a method for testing a high-voltage direct current transmission phase selection closing device through a large resistor. Background Art
[0002] High-voltage circuit breakers are important primary equipment used for switching loads and making and breaking currents. During the process of making and breaking, they will produce transient phenomena such as opening and closing surge currents and overvoltages, which will have a negative impact on the stable operation, expected life, and status of power equipment. In particular, for reactive power control in DC projects commutated by the power grid, there is a situation where AC filters are frequently switched on and off. If the switching is not synchronized, it will cause zero-sequence voltage abnormalities in the system. Large zero-sequence changes may trigger the prediction action of the DC transmission system's commutation failure, increase the arc extinction angle to prevent commutation failure, and then cause power fluctuations in the AC and DC systems, posing a huge challenge to the safe and stable operation of the power grid. At the same time, high-frequency, high-amplitude overvoltages and large currents will be generated at the moment of being switched on at different times, which will cause very serious insulation shocks to the AC bus, AC filter capacitor and reactance components, and the circuit breaker body. The purpose of the phase-selective closing device is to control the circuit breaker to complete the opening and closing operation under the most favorable voltage or current phase conditions. The inrush current and overvoltage generated during the opening and closing process will be greatly weakened. However, due to the influence of the phase-selective closing device's own accuracy and control parameters, as well as the aging and moisture of the circuit breaker's auxiliary contacts, the closing accuracy of the device often decreases, which will affect the confidence of the phase-selective closing device results. Therefore, it is necessary to test the control accuracy and reliability of the phase-selective closing device to determine the accuracy of the device.
[0003] At present, in actual working process, a large current generator, an external recording device and a phase-selective closing device are often used to manually switch the circuit breaker on and off several times when it is static, and the average closing time is used for verification. This method simulates the transient process with a steady-state average approximation, and cannot accurately capture the action moment of the phase-selective closing device, that is, it cannot accurately capture key parameters such as the closing time, resulting in low accuracy of the test results of the phase-selective closing device. Summary of the invention
[0004] In order to solve the above technical problems, the present invention proposes a method for testing a high-voltage direct current transmission phase selection and closing device through a large resistor, which improves the accuracy of the phase selection and closing verification method and improves the test accuracy of the phase selection and closing device.
[0005] A method for testing a high-voltage direct current transmission phase selection and closing device through a large resistor, comprising: a phase selection and closing device, a transient large current generator, an AC circuit breaker, a current transformer, a voltage transformer, a large resistor, a relay protection tester, a wireless voltage phase reference source and an AC bus;
[0006] The transient high current generator outputs a current with an amplitude of 300A under the start command of the operator's wireless control;
[0007] After the transient high current generator is started, the current on the primary circuit passes through the large resistor and the parallel circuit of the circuit breaker and the current transformer to simulate the steady state of the circuit breaker. At this time, the circuit breaker is in the open state, and there is no current value on the secondary side of the current transformer.
[0008] The closing command is sent to the phase selection and gate device through the relay protection device. The phase selection and gate device sends a closing command to the AC circuit breaker according to the phase selection reference voltage. When the AC circuit breaker is turned on, the circuit breaker and the current transformer are connected in series, and the current passes through the circuit breaker circuit. The secondary side of the current transformer collects the current and sets the current transformer ratio to k1 / 1. At this time, the current on the secondary circuit of the current transformer is k2.
[0009] The relay protection tester calculates the phase angle difference between the phase selection reference voltage and the collected current k2 as A1, and the phase selection and gate device calculates the phase angle difference between the phase selection reference voltage and the collected current k2 as A2. The relay protection tester determines whether A1 and A2 are consistent to confirm the accuracy of the phase angle opened by the phase selection and gate device. If they are consistent, the phase angle opened by the phase selection and closing device is accurate and meets the requirements; if they are inconsistent, there is a deviation between the phase angle opened by the phase selection and closing device and the actual closing phase, and the closing phase angle opened by the phase selection and gate device needs to be readjusted.
[0010] Preferably, the AC circuit breaker is connected in series with the current transformer and then connected in parallel with the large resistor.
[0011] Preferably, a switching switch is provided on the large resistor side of the circuit after the AC circuit breaker and the current transformer are connected in series and in parallel with the large resistor. When the switching switch is closed, the large resistor and the AC circuit breaker and the current transformer are connected in parallel; when the switching switch is opened, the large resistor exits the parallel circuit with the AC circuit breaker and the current transformer; it can be understood that during testing, the switching switch is closed.
[0012] Preferably, the large resistor and the transient large current generator are connected in parallel.
[0013] Preferably, the current transformer is located on a side of the AC circuit breaker away from the AC busbar.
[0014] Preferably, the current transformer is electrically connected to the relay protection tester, the relay protection tester is electrically connected to the phase selection and switch device; the phase selection and switch device is electrically connected to the AC circuit breaker; and the voltage transformer is connected to the AC bus.
[0015] Preferably, the wireless voltage phase reference source, the phase selection and switching device and the relay protection tester are communicatively connected; the wireless voltage phase reference source collects the AC bus system voltage and outputs a phase selection reference voltage, which is sent to the relay protection tester and the phase selection and switching device via a reference voltage wireless generating device.
[0016] Preferably, there is a first test time difference t1 between the relay protection tester and the phase selection and switching device, and a second test time difference t2 between the phase selection and switching device and the AC circuit breaker. If A1 is equal to A2, then during the test, the AC circuit breaker performs synchronous closing and opening.
[0017] Preferably, when t1 < t2, if A1 > A2, then t1 is increased by 30 - 800 milliseconds; or, when t1 < t2, if A1 > A2, then t2 is decreased by 50 - 500 milliseconds.
[0018] Preferably, when t1 > t2, if A1 < A2, then t1 is increased by 50 - 600 milliseconds; or, when t1 > t2, if A1 < A2, then t2 is decreased by 60 - 800 milliseconds.
[0019] In addition, the present invention provides a test method for the phase selection and closing device of high - voltage DC transmission through a large resistor, including a transient large - current generator, a relay protection tester, a phase selection and closing device, a wireless voltage phase reference source, and a large resistor. First, the transient large - current generator provides excitation. The transient large - current generator can be controlled to turn on and off wirelessly. The current excitation is applied to the primary circuit to provide three - phase current. The protection tester and the phase selection and closing device collect the current values through the secondary side of the current transformer connected in series with the circuit breaker. The large resistor is connected in parallel with the circuit breaker and the current transformer. The reference voltage of the phase selection and closing device is obtained from the secondary side of the voltage transformer through the wireless voltage phase reference source. The relay protection tester sends a closing command to the phase selection and closing device. The phase selection and closing device issues a closing command to the closing circuit of the circuit breaker according to the phase selection reference voltage provided by the wireless voltage phase reference source, realizing the fixed - phase switching of the circuit breaker. When the circuit breaker is not closed, under the action of the current source excitation in the primary circuit, the current forms a loop through the large resistor, and there is no current on the secondary side of the current transformer. At the moment when the circuit breaker closes, the primary - circuit current is shunted through the circuit breaker, and the current acquisition circuits of the phase selection and closing device and the relay protection tester will collect the current on the secondary side of the current transformer. The relay protection tester judges whether the phase angles are consistent based on the collected current value and the phase selection reference voltage.
[0020] Preferably, for the large - group AC filter, due to the power outage of the AC bus, the reference voltage is determined by artificially outputting the voltage phase angle and amplitude on the secondary side of the voltage transformer; for the small - group AC filter, the reference voltage is selected as the value on the secondary side of the voltage transformer.
[0021] Beneficial effects: The accuracy of the phase selection and closing verification method is improved, and the test accuracy of the phase selection and closing device is improved. Description of the Drawings
[0022] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:
[0023] Figure 1 A schematic diagram of a method for testing a high-voltage direct current transmission phase selection and closing device through a large resistor provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0024] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0025] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0026] Embodiment 1
[0027] Figure 1 As shown, a method for testing a high-voltage direct current transmission phase selection and closing device through a large resistor includes: a phase selection and closing device, a transient large current generator, an AC circuit breaker, a current transformer, a voltage transformer, a large resistor, a relay protection tester, a wireless voltage phase reference source and an AC bus.
[0028] Preferably, the AC circuit breaker is connected in series with the current transformer and then connected in parallel with the large resistor.
[0029] Preferably, a switching switch is provided on the large resistor side of the circuit after the AC circuit breaker and the current transformer are connected in series and in parallel with the large resistor. When the switching switch is closed, the large resistor and the AC circuit breaker and the current transformer are connected in parallel; when the switching switch is opened, the large resistor exits the parallel circuit with the AC circuit breaker and the current transformer; it can be understood that during testing, the switching switch is closed.
[0030] Optionally, the switching switch is remotely operated.
[0031] Preferably, the large resistor and the transient large current generator are connected in parallel.
[0032] Preferably, the current transformer is located on the side of the AC circuit breaker away from the AC busbar.
[0033] Preferably, the current transformer is electrically connected to the phase selection and gate device.
[0034] Preferably, the current transformer is electrically connected to the relay protection tester, and the relay protection tester is electrically connected to the phase selection and gate device.
[0035] Preferably, the phase selection and brake device is electrically connected to the AC circuit breaker.
[0036] Preferably, the voltage transformer is connected to the AC bus.
[0037] Preferably, the AC circuit breaker is connected to the AC busbar via a knife switch.
[0038] Preferably, the wireless voltage phase reference source, the phase selection and switching device and the relay protection tester are communicatively connected.
[0039] Optionally, a wireless voltage phase reference source collects the AC bus system voltage and outputs a phase selection reference voltage. Optionally, the phase selection reference voltage is 100V, which is sent to the relay protection tester and the phase selection and gate device via a reference voltage wireless generating device.
[0040] Optionally, the transient high current generator outputs a current with an amplitude of 300A under a start command of a wireless control by an operator.
[0041] After the transient high current generator is started, the current in the primary circuit passes through a large resistor and a parallel circuit of the circuit breaker and the current transformer to simulate the steady state of the circuit breaker. At this time, the circuit breaker is in the open state and there is no current value on the secondary side of the current transformer.
[0042] The closing command is sent to the phase selection and gate device through the relay protection device. The phase selection and gate device sends a closing command to the AC circuit breaker according to the phase selection reference voltage. When the AC circuit breaker is turned on, the circuit breaker and the current transformer are connected in series, and the current passes through the circuit breaker circuit. The secondary side of the current transformer collects the current, and the current transformer ratio is set to k1 / 1, and k1 can be selected to be 5000. At this time, the current on the secondary circuit of the current transformer is k2, and k2 can be selected to be 0.06A.
[0043] The phase angle difference between the reference voltage for phase selection calculated by the relay protection tester and the current k2 collected is A1, and the phase angle difference between the reference voltage for phase selection calculated by the phase selection and switching device and the current k2 collected is A2. The relay protection tester determines whether A1 and A2 are consistent to confirm the accuracy of the phase angle sent out by the phase selection and switching device. If they are consistent, the phase angle sent out by the phase selection and switching device is accurate and meets the requirements; if they are inconsistent, there is a deviation between the phase angle sent out by the phase selection and switching device and the actual closing phase angle, and the closing phase angle sent out by the phase selection and switching device needs to be readjusted.
[0044] Preferably, there is a first test time difference t1 between the relay protection tester and the phase selection and switching device, and a second test time difference t2 between the phase selection and switching device and the AC circuit breaker. If A1 is equal to A2, the AC circuit breaker performs synchronous closing during the test.
[0045] Preferably, the first test time difference t1 can be the time between the relay protection tester sending out a closing operation and the phase selection and switching device sending out a closing command; the second test time difference t2 can be the time between the phase selection and switching device sending out a closing command and the AC circuit breaker operating.
[0046] Preferably, when t1 < t2, if A1 > A2, then t1 increases by 30 - 800 milliseconds.
[0047] Preferably, when t1 < t2, if A1 > A2, then t2 decreases by 50 - 500 milliseconds.
[0048] Preferably, when t1 < t2, if A1 < A2, then t1 decreases by 50 - 600 milliseconds.
[0049] Preferably, when t1 < t2, if A1 < A2, then t2 increases by 60 - 800 milliseconds.
[0050] Preferably, when t1 > t2, if A1 > A2, then t1 decreases by 30 - 800 milliseconds.
[0051] Preferably, when t1 > t2, if A1 > A2, then t2 increases by 50 - 500 milliseconds.
[0052] Preferably, when t1 > t2, if A1 < A2, then t1 increases by 50 - 600 milliseconds.
[0053] Preferably, when t1 > t2, if A1 < A2, then t2 decreases by 60 - 800 milliseconds.
[0054] Preferably, when t1 = t2, if A1 > A2, then t1 decreases by 100 - 600 milliseconds.
[0055] Preferably, when t1 = t2, if A1 > A2, then t2 increases by 100 - 500 milliseconds.
[0056] Preferably, when t1 = t2, if A1 < A2, then t1 is increased by 100 - 600 milliseconds.
[0057] Preferably, when t1 = t2, if A1 < A2, then t2 is decreased by 1000 - 500 milliseconds.
[0058] Optionally, before the transient large current generator is started, the switch between the AC circuit breaker and the AC busbar is in the closed state.
[0059] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.
[0060] It should be noted that the serial numbers of the embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.
[0061] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, and any combination of the embodiments or solutions can be included in the patent protection scope of the present invention by the same token.
Claims
1. A method for testing a high voltage direct current transmission phase selection closing device through a large resistor, characterized in that: Including: Phase selection and switching device, transient high current generator, AC circuit breaker, current transformer, voltage transformer, large resistor, relay protection tester, wireless voltage phase reference source and AC busbar; The transient high current generator outputs a current with an amplitude of 300 A under the start command wirelessly controlled by the operator; After the transient high current generator starts, the current on the primary circuit simulates the steady state of the circuit breaker through the parallel circuit of the large resistor, the circuit breaker and the current transformer. At this time, the circuit breaker is in the open state and there is no current value on the secondary side of the current transformer; The closing command is sent to the phase selection and switching device through the relay protection device. The phase selection and switching device issues a closing command to the AC circuit breaker according to the phase selection reference voltage. When the AC circuit breaker conducts, the circuit breaker is in series with the current transformer, and the current passes through the circuit breaker loop. The current transformer collects the current on the secondary side. The current transformer ratio is set to k1 / 1, and the current on the secondary circuit of the current transformer at this time is k2. The relay protection tester calculates the phase angle difference between the phase selection reference voltage and the collected current k2 as A1, and the phase selection and switching device calculates the phase angle difference between the phase selection reference voltage and the collected current k2 as A2. The relay protection tester judges whether A1 and A2 are consistent to confirm the accuracy of the phase angle issued by the phase selection and switching device. If they are consistent, the phase angle issued by the phase selection and closing device is accurate and meets the requirements; If they are not consistent, there is a deviation between the phase angle issued by the phase selection and closing device and the actual closing phase, and the closing phase angle issued by the phase selection and switching device needs to be readjusted.
2. The method according to claim 1, characterized in that The AC circuit breaker is in series with the current transformer and then in parallel with the large resistor.
3. The method according to claim 1, characterized in that A switching switch is provided on the large resistor side of the parallel circuit of the AC circuit breaker in series with the current transformer and the large resistor. When the switching switch is closed, the large resistor is in parallel with the AC circuit breaker and the current transformer; when the switching switch is open, the large resistor exits the parallel circuit with the AC circuit breaker and the current transformer; it can be understood that during the test, the switching switch is closed.
4. The method according to claim 1, characterized in that The large resistor is in parallel with the transient high current generator.
5. The method according to claim 1, characterized in that The current transformer is located on the side of the AC circuit breaker away from the AC busbar.
6. The method according to claim 1, characterized in that The current transformer is electrically connected to the relay protection tester, and the relay protection tester is electrically connected to the phase selection and switching device; the phase selection and switching device is electrically connected to the AC circuit breaker; the voltage transformer is connected to the AC busbar.
7. The method according to claim 1, characterized in that The wireless voltage phase reference source, the phase selection and switching device and the relay protection tester are communicatively connected; the wireless voltage phase reference source collects the system voltage of the AC busbar and outputs the phase selection reference voltage, which is sent to the relay protection tester and the phase selection and switching device through the reference voltage wireless generating device.
8. The method according to claim 1, characterized in that There is a first test time difference t1 between the relay protection tester and the phase selection and switching device, and a second test time difference t2 between the phase selection and switching device and the AC circuit breaker. If A1 is equal to A2, the AC circuit breaker is switched and closed synchronously during the test.
9. The method according to claim 8, characterized in that When t1 < t2, if A1 > A2, then t1 is increased by 30 - 800 milliseconds; or, when t1 < t2, if A1 > A2, then t2 is decreased by 50 - 500 milliseconds.
10. The method according to claim 8, characterized in that When t1 > t2, if A1 < A2, then t1 is increased by 50 - 600 milliseconds; or, when t1 > t2, if A1 < A2, then t2 is decreased by 60 - 800 milliseconds.