An alternating current withstand voltage test device based on low voltage compensation frequency-locked phase

Abstract

The utility model discloses a kind of based on low-voltage compensation frequency-locked phase ac withstand voltage test device, including frequency-locked phase power supply, low-voltage compensation circuit, frequency phase synchronous tracking circuit, high-voltage test transformer and test circuit;Frequency-locked phase power supply is connected with the first winding of high-voltage test transformer via low-voltage compensation circuit, and measurement winding is connected with frequency-locked phase power supply via frequency phase synchronous tracking circuit;The second winding of high-voltage test transformer is exported via high-voltage test equipment and disconnecting switch, and voltage transformer is connected between frequency phase synchronous tracking circuit and disconnecting switch.The utility model can effectively reduce the power supply required for test by low-voltage compensation in power supply side, reduce the performance requirement to reactor;Low-voltage side is also provided with measurement winding, can directly measure high-voltage voltage value, without using conventional capacitor voltage divider, reduce cost, also avoid capacitor voltage divider field assembly process, can be directly vehicle-mounted and without unloading field test, improve work efficiency.

Description

Technical Field

[0001] This utility model relates to the field of AC withstand voltage testing technology for high-voltage equipment, specifically to an AC withstand voltage testing device based on low-voltage compensation frequency-locked phase-locked circuit. Background Technology

[0002] The same-frequency, same-phase AC withstand voltage test device is a key piece of equipment used for conducting AC withstand voltage tests on power equipment under uninterrupted power supply conditions. This type of device can safely and accurately test power equipment by generating a test voltage with the same frequency and phase as the operating voltage without disconnecting the operating bus, effectively ensuring the reliability and stability of the power grid. Existing technologies generally use the inductance-adjustable series resonance method as the core, achieving system resonance matching by adjusting the inductance value of the reactor, thereby completing the withstand voltage test under uninterrupted power supply conditions. This technology has been widely applied in the field testing of various high-voltage electrical equipment.

[0003] However, existing inductance-adjustable series resonant methods still have significant limitations in practical applications. This method relies on high-voltage adjustable reactors, which not only require extremely high insulation performance and adjustment accuracy but also need to cover a wide range of inductance values, leading to complex equipment manufacturing and high costs. Furthermore, field testing requires transporting multiple heavy pieces of equipment (including in-phase and frequency test power supplies, test transformers, protective resistors, reactors, and voltage measuring devices), and unloading, assembling, and debugging on-site, resulting in lengthy preparation time and severely impacting testing efficiency. The increased cost of machinery and the extended testing time also negatively affect the performance of the testing department. Utility Model Content

[0004] The purpose of this invention is to provide an AC withstand voltage test device based on low-voltage compensation, frequency-locked, and phase-locked circuits. By providing low-voltage compensation on the power supply side, the power supply required for the test can be effectively reduced, as well as the voltage requirements of the reactor. Moreover, the low-voltage side is equipped with a measuring winding that can directly measure the high-voltage value, eliminating the need for a measuring capacitor voltage divider required for conventional tests. This effectively reduces costs and eliminates the need for on-site assembly of the capacitor voltage divider. The device can be directly mounted on a vehicle and the on-site test can be completed without unloading, improving on-site work efficiency and accelerating the commissioning time of power equipment.

[0005] The specific technical solution is as follows: An AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit includes a frequency-locked phase-locked power supply, a low-voltage compensation circuit, a frequency and phase synchronization tracking circuit, a high-voltage test transformer, and a test circuit. The high-voltage test transformer includes a first end, a second end, and an iron core between the two ends. The first end includes a first winding and a measuring winding, and the second end includes a second winding. The frequency-locked phase-locked power supply is connected to the first winding of the high-voltage test transformer via the low-voltage compensation circuit, and the measuring winding is connected to the frequency-locked phase-locked power supply via the frequency and phase synchronization tracking circuit. The first transmission direction of the second winding is grounded, and the second transmission direction of the second winding is connected to the test circuit. The test circuit is also connected to the frequency and phase synchronization tracking circuit. The test circuit includes high-voltage test equipment.

[0006] Optionally, the low-voltage compensation circuit includes a gap control controller connected in parallel between the frequency-locked phase-locked power supply and the first terminal. The gap control controller includes a series-connected adjustable reactor and a resistor. The adjustable reactor can change the inductance by adjusting the gap in real time, thereby compensating for the capacitive reactive current generated by the capacitive load on the high-voltage side. The series resistor is mainly used to suppress resonance that may occur in the compensation circuit, increase system damping, prevent oscillation, and improve system stability.

[0007] Optionally, the frequency-locked phase-locked power supply includes an AC-DC rectifier circuit, a DC-AC inverter circuit, an MCU, and an LC filter circuit. The AC-DC rectifier circuit is connected to the DC-AC inverter circuit, the MCU is connected to the DC-AC inverter circuit, and the DC-AC inverter circuit outputs to the outside via the LC filter circuit.

[0008] Optionally, the frequency phase synchronization tracking circuit includes an operational amplifier, voltage divider resistors, and an AD chip; the operational amplifier is connected to the AD chip and the test circuit respectively; the voltage divider resistors are connected between the AD chip and ground; and the AD chip is connected to the MCU.

[0009] Optionally, the test circuit also includes a disconnecting switch and a voltage transformer, which are output to the outside via the high-voltage test equipment and the disconnecting switch in sequence. The voltage transformer is connected between the AD chip and the disconnecting switch.

[0010] Optionally, the voltage transformer is a capacitive voltage transformer. Capacitive voltage transformers are effectively suitable for high-voltage testing applications.

[0011] Optionally, the voltage transformer is grounded.

[0012] Optionally, the voltage transformer used is model ZMPT. ZMPT voltage transformers are characterized by small size, high accuracy, good linearity, and low cost.

[0013] Optionally, the operational amplifier is a low-offset operational amplifier with an offset voltage of less than 100μV. Using a low-offset operational amplifier can ensure signal accuracy.

[0014] Optionally, the AD chip employs a successive approximation analog-to-digital converter (ADC). A successive approximation ADC offers low latency and is suitable for processing medium- to high-frequency AC signals.

[0015] The advantages of this utility model compared with the prior art are: This invention effectively reduces the power supply required for testing by providing low-voltage compensation on the power supply side, and also reduces the voltage requirements for reactors. Furthermore, the low-voltage side is equipped with a measuring winding that can directly measure high-voltage values, eliminating the need for a measuring capacitor voltage divider required for conventional testing, effectively reducing costs, and also eliminating the need for on-site assembly of the capacitor voltage divider. It can be directly mounted on a vehicle and completed on-site testing without unloading, improving on-site work efficiency and accelerating the commissioning time of power equipment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit. Figure 2 This is a schematic diagram of a low-voltage compensated frequency-locked phase-locked AC withstand voltage test device; Figure 3 This is a schematic diagram of a model of an AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit for actual installation without unloading from the vehicle. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0018] like Figure 1 The diagram shown is a schematic of an AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit; as shown... Figure 2 The diagram shown is a structural schematic of an AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit; combined with Figure 1 and Figure 2 As shown, by setting a low-voltage compensation circuit and a frequency phase synchronization tracking circuit on the low-voltage power supply side, the voltage requirements on the power supply side during transformer testing are effectively reduced, eliminating the need for conventional capacitor voltage dividers, making the test device convenient for vehicle-mounted use.

[0019] A low-voltage compensation-based frequency-locked phase-locked AC withstand voltage test device specifically includes a frequency-locked phase-locked power supply, a low-voltage compensation circuit, a frequency and phase synchronization tracking circuit, a high-voltage test transformer, and a test circuit. The frequency-locked phase-locked power supply is used to provide stable power supply, the high-voltage test transformer is used to transform the voltage to test the test circuit, the frequency and phase synchronization tracking circuit is used to form a feedback loop, and the low-voltage compensation circuit is used to perform low-voltage compensation on the low-voltage side during transformation.

[0020] The high-voltage test transformer includes a first end, a second end, and an iron core between the two ends. The first end includes a first winding and a measuring winding, and the second end includes a second winding. A frequency-locked phase-locked power supply is connected to the first winding of the high-voltage test transformer via a low-voltage compensation circuit, and the measuring winding is connected to the frequency-locked phase-locked power supply via a frequency-phase synchronization tracking circuit. The first transmission direction of the second winding is grounded, and the second transmission direction of the second winding is connected to the test circuit. The test circuit is also connected to the frequency-phase synchronization tracking circuit, forming a feedback loop. The test circuit includes high-voltage test equipment, which is... Figure 1 CB in the middle.

[0021] The low-voltage compensation circuit includes a gap adjustment controller connected in parallel between the frequency-locked phase-locked power supply and the first terminal. The gap adjustment controller includes a series-connected adjustable reactor and a resistor. Figure 1 and 2 In this diagram, RL represents resistance, and L represents adjustable inductance reactor. An adjustable inductance reactor is a device that adjusts inductance by changing the size of the air gap (i.e., magnetic gap) in the magnetic circuit. By adjusting the magnetic gap in real time, the adjustable inductance reactor can change the inductance, thereby compensating for the capacitive reactive current generated by the capacitive load on the high-voltage side. The series resistor is mainly used to suppress resonance that may occur in the compensation circuit, increase system damping, prevent oscillation, and improve system stability.

[0022] The frequency-locked phase-locked power supply includes an AC-DC rectifier circuit, a DC-AC inverter circuit, an MCU, and an LC filter circuit. The AC-DC rectifier circuit is connected to the DC-AC inverter circuit, the MCU is connected to the DC-AC inverter circuit, and the DC-AC inverter circuit outputs power through the LC filter circuit, providing a stable power supply. The frequency and phase synchronization tracking circuit includes an operational amplifier, voltage divider resistors, and an AD chip. The operational amplifier is connected to both the AD chip and the test circuit. The voltage divider resistors are connected between the AD chip and ground. The AD chip is connected to the MCU. The test circuit also includes disconnect switches and voltage transformers. There are two disconnect switches, DS1 and DS2, and the voltage transformers are... Figure 1 and Figure 2The voltage transformer (PT) in the circuit outputs power sequentially through the high-voltage testing equipment and the disconnecting switch. The voltage transformer connects the AD chip and the disconnecting switch. Based on feedback from the measurement winding and the testing circuit, the MCU can accurately adjust the inductor in the low-voltage compensation circuit for low-voltage compensation. Specifically, the MCU's calculation and control process is well-known in the field of electrical engineering and will not be elaborated upon here. Furthermore, the specific operation and control flow of the MCU is not protected by this application.

[0023] For the voltage transformer, the ZMPT (miniature voltage transformer, such as ZMPT101B) model is used. ZMPT voltage transformers are characterized by their small size, high accuracy, good linearity, and low cost. The operational amplifier is a low-offset operational amplifier with an offset voltage below 100μV, such as the OP07C model (offset voltage parameter 75μV). Using this type of low-offset operational amplifier ensures signal accuracy. The AD chip is a successive approximation analog-to-digital converter. This type of AD chip has low latency and is suitable for processing medium- and high-frequency AC signals.

[0024] like Figure 3 The diagram shown is a schematic of a low-voltage compensated frequency-locked phase-locked AC withstand voltage test device, which is installed on the vehicle without being removed. The test device of this application can be directly tested on the vehicle without disassembly and installation, which greatly improves convenience and efficiency.

[0025] In summary, this application effectively reduces the power supply required for testing by using low-voltage compensation on the power supply side, and also reduces the voltage requirements for reactors. Moreover, the low-voltage side is equipped with a measuring winding that can directly measure high-voltage values, eliminating the need for a measuring capacitor voltage divider required for conventional testing, effectively reducing costs, and eliminating the on-site assembly process of the capacitor voltage divider. It can be directly mounted on a vehicle and completed on-site testing without unloading, improving on-site work efficiency and accelerating the commissioning time of power equipment, demonstrating significant progress.

[0026] The above embodiments are only for illustrating the technical concept of this utility model and should not be construed as limiting the scope of protection of this utility model. Any modifications made to the technical solution based on the technical concept proposed by this utility model shall fall within the scope of protection of this utility model.

Claims

1. A low-voltage compensated frequency-locked phase-locked AC withstand voltage test device, characterized in that, The system includes a frequency-locked phase-locked power supply, a low-voltage compensation circuit, a frequency and phase synchronization tracking circuit, a high-voltage test transformer, and a test circuit. The high-voltage test transformer includes a first end, a second end, and an iron core between the two ends. The first end includes a first winding and a measuring winding, and the second end includes a second winding. The frequency-locked phase-locked power supply is connected to the first winding of the high-voltage test transformer via the low-voltage compensation circuit. The measuring winding is connected to the frequency-locked phase-locked power supply via the frequency and phase synchronization tracking circuit. The first transmission direction of the second winding is grounded, and the second transmission direction of the second winding is connected to the test circuit. The test circuit is also connected to the frequency and phase synchronization tracking circuit. The test circuit includes high-voltage test equipment.

2. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 1, characterized in that... The low-voltage compensation circuit includes a gap adjustment controller connected in parallel between the frequency-locked phase-locked power supply and the first terminal. The gap adjustment controller includes a series-connected adjustable inductor and a resistor.

3. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 1, characterized in that, The frequency-locked phase-locked power supply includes an AC-DC rectifier circuit, a DC-AC inverter circuit, an MCU, and an LC filter circuit. The AC-DC rectifier circuit is connected to the DC-AC inverter circuit, the MCU is connected to the DC-AC inverter circuit, and the DC-AC inverter circuit outputs to the outside via the LC filter circuit.

4. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 3, characterized in that, The frequency phase synchronization tracking circuit includes an operational amplifier, voltage divider resistors, and an AD chip; the operational amplifier is connected to the AD chip and the test circuit respectively; the voltage divider resistors are connected between the AD chip and ground; the AD chip is connected to the MCU.

5. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 4, characterized in that, The test circuit also includes a disconnecting switch and a voltage transformer, which are output to the outside via the high-voltage test equipment and the disconnecting switch in sequence. The voltage transformer is connected between the AD chip and the disconnecting switch.

6. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 5, characterized in that, The voltage transformer is a capacitive voltage transformer.

7. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 5, characterized in that, The voltage transformer is grounded.

8. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 5, characterized in that, The voltage transformer used is model ZMPT.

9. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked circuit according to claim 4, characterized in that, The operational amplifier is a low-offset operational amplifier with an offset voltage of less than 100μV.

10. The AC withstand voltage test device based on low-voltage compensation frequency-locked phase-locked loop according to claim 4, characterized in that, The AD chip uses a successive approximation analog-to-digital converter.

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