A comprehensive detection and calibration instrument for non-electric quantity protection device of transformer

Abstract

This invention discloses a comprehensive testing and calibration instrument suitable for non-electrical quantity protection devices of transformers, relating to the field of transformer testing and protection. It includes a central processing unit, signal conditioning and sampling circuits, a drive circuit, a display circuit, a clock circuit, a communication circuit, and a power supply. The central processing unit includes a main controller; the signal conditioning and sampling circuit includes multiple analog-to-digital converters (AD), digital-to-analog converters (DA), a current signal conditioning module, and a voltage signal conditioning module; the display circuit includes an LCD screen; and all circuits are connected via communication circuits; the power supply uses a rechargeable power supply; the main controller is connected to multiple test modules via the signal conditioning and sampling circuits; the test modules include an insulation / withstand voltage / continuity test module, a temperature measurement module, and a gas relay test module. This invention can perform various tests, improves experimental accuracy, simplifies calibration steps, and greatly shortens calibration time, making testing accurate, simple, time-saving, and labor-saving.

Description

Technical Field

[0001] This invention relates to the field of transformer testing and protection, specifically to a comprehensive testing and calibration instrument applicable to non-electrical protection devices of transformers. Background Technology

[0002] The State Grid Shanxi Provincial Maintenance Company is responsible for the operation, maintenance, and management of all ultra-high voltage (UHV) and extra-high voltage (EHV) substations in Shanxi Province, including 3 1000 kV substations, 1 800 kV converter station, and 27 500 kV substations (switching stations). As core hubs of the Shanxi power grid, these UHV and EHV substations undertake crucial power transmission and transformation tasks. The most critical primary equipment in these substations is the main transformer, which functions as a transmission, distribution, and voltage conversion hub in the power grid. Its safe and reliable operation is key to ensuring the stability of the power system. To improve equipment reliability and ensure equipment safety, large power transformers are equipped with both electrical and non-electrical quantity protections. If these protections function correctly and promptly disconnect the power supply during internal transformer faults, they limit the conversion of electrical energy into heat and chemical energy, as well as the drastic expansion of the oil volume and the decomposition of insulating paper and insulating oil into gas. This keeps the fault within acceptable limits, effectively protecting the main transformer, preventing the fault from escalating, and reducing losses. Electrical relay protection systems for power transformers, such as differential protection, instantaneous overcurrent protection, and zero-sequence current protection, are not sensitive to internal transformer faults. This is because internal transformer faults generally begin with inter-turn short circuits. Although the fault current within the short-circuited turns is large, it is not reflected in the line current. The power supply can only be cut off when the fault develops into a multi-turn short circuit or a short circuit to ground. This is an inherent characteristic of electrical protection. When the transformer fault falls outside the sensitivity or fault type of electrical protection, non-electrical protection must be relied upon to ensure the transformer's safety. Therefore, non-electrical protection is a crucial component of transformer protection, and the completeness and reliability of its functions directly affect the safe and stable operation of the transformer. Thus, a device is needed to detect whether non-electrical protection devices are functioning correctly, thereby ensuring the safe and stable operation of the transformer.

[0003] Existing non-electrical quantity protection device testing equipment has several drawbacks: ① During insulation resistance, withstand voltage, and continuity tests on transformers, the numerous test items necessitate rewiring for each measurement, such as insulation testing between different phases. This cumbersome wiring not only adds to the workload but also increases the probability of errors and prolongs maintenance time. Therefore, a solution to this complex wiring problem is desired. ② In the temperature detection and verification process of transformers, the temperature signal is converted into an electrical signal by a thermistor. In common temperature detection, a 4-20mA electrical signal can reflect a temperature range of 160℃. However, the problem is that only the electrical signal is directly readable; obtaining the specific temperature requires calculation using formulas, and different models of temperature detection devices use different formulas, which is cumbersome and not intuitive, making temperature detection complex. ③ The testing of gas relays has also been problematic. During on-site testing, it is difficult to inject suitable gas into the transformer to verify the reliable operation of the gas relay. The difficulty lies in the strict requirements for the pressure and volume of the gas injected into the transformer, and the requirement that the gas must not contaminate the transformer oil.

[0004] Considering the aforementioned problems with the detection of existing non-electrical quantity protection devices, it is necessary to design or improve the detection device for existing non-electrical quantity protection devices. Summary of the Invention

[0005] To address the lack of specialized instruments for the routine maintenance of non-electrical quantity protection devices of main transformers in the State Grid's operation and maintenance system, this invention provides a comprehensive testing and calibration instrument suitable for transformer non-electrical quantity protection devices.

[0006] This invention is achieved through the following technical solution: a comprehensive testing and calibration instrument suitable for non-electrical quantity protection devices of transformers, comprising a central processing unit, a signal conditioning and sampling circuit, a drive circuit, a display circuit, a clock circuit, a communication circuit, and a power supply device; the central processing unit includes a main controller; the signal conditioning and sampling circuit includes multiple analog-to-digital converters (AD), digital-to-analog converters (DA), a current signal conditioning module, and a voltage signal conditioning module; the display circuit includes an LCD screen, and the various circuits are connected to each other through the communication circuit; the power supply device uses a charging power supply; the main controller is connected to multiple test modules through the signal conditioning and sampling circuit, and the LCD screen is connected to the main controller through an RS232 serial interface; the main controller provides 5~15V power to the LCD screen; the main controller contains multiple analog-to-digital converters (AD), digital-to-analog converters (DA), and I / O interfaces; the test modules include an insulation / withstand voltage / continuity test module, a temperature measurement module, and a gas relay test module. The insulation / withstand voltage / continuity test module includes a DC high-voltage module, a boost section, high-voltage relay I, high-voltage relay II, a high-voltage signal conditioning module, a current signal conditioning module, and multiple insulation / withstand voltage / continuity test terminals. Each insulation / withstand voltage / continuity test terminal also includes a grounding terminal. The boost section includes an AC power module and a power frequency transformer boost module. The AC power module outputs AC voltage to the power frequency transformer boost module. The AC power module and the DC high-voltage module are connected together to a digital-to-analog converter (DA) interface of the main controller. The high-voltage relay I contains two switches. The DC high-voltage module and the power frequency transformer boost module... The modules are connected to high-voltage relay II via corresponding switches within high-voltage relay I. High-voltage relay II contains multiple pairs of high-voltage on / off switches and current acquisition switches, all controlled by a drive circuit. Each pair of high-voltage on / off switches and current acquisition switches is connected in series with each insulation / withstand voltage / continuity test terminal (excluding the grounding terminal). All high-voltage on / off switches are connected in parallel and then in series with high-voltage relay I. All current acquisition switches are connected in parallel and then in series with a current signal conditioning module. The current signal conditioning module inputs a signal to the analog-to-digital converter (AD) interface of the main controller. The grounding terminal is directly connected to the current signal conditioning module. The temperature measurement module includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal is connected in series with the current signal conditioning module and then inputs a signal to the analog-to-digital converter (AD) interface of the main controller.The gas relay test module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller, and the venting solenoid valve is controlled by another I / O interface of the main controller. The solenoid valve controls the opening and closing of the inert gas tank, and the venting solenoid valve controls the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer. The flow sensor and the pressure sensor are located on the gas path of the inert gas tank. The flow sensor and the pressure sensor respectively input signals to two different analog-to-digital converter interfaces (AD) on the main controller.

[0007] This invention provides a comprehensive testing and calibration instrument for transformer non-electrical protection devices. It integrates insulation / withstand voltage / continuity testing, temperature measurement modules, and gas relay testing into a single instrument. The instrument mainly includes a central processing unit, signal conditioning and sampling circuit, drive circuit, display circuit, clock circuit, communication circuit, and power supply. The main controller, the central processing unit, functions to: 1) display system voltage, current, and tap changer position signals; and 2) compare the sampled signals with set values ​​to determine if voltage regulation conditions are met. If the conditions are met, a voltage regulation command is sent to the drive circuit; otherwise, no voltage regulation command is issued. The signal conditioning and sampling circuit includes multiple analog-to-digital (AD) conversion interfaces, digital-to-analog (DA) conversion interfaces, a current signal conditioning module, and a voltage signal conditioning module. This circuit's function is to adjust and transform the signal values ​​and input ranges provided by the voltage and current detection circuits when they do not match the A / D conversion chip. The signal conditioning circuit converts the detected voltage, current, and bipolar signals into unipolar 0-5V signals before A / D conversion. The drive circuit drives the corresponding fully controlled power electronic devices to switch according to the modulated waveform. The display circuit includes an LCD screen, and all circuits are connected via communication circuits; a clock circuit is used for timing. The power supply uses a rechargeable power supply for easy testing. The main controller is connected to multiple test modules through signal conditioning and sampling circuits. These test modules are used for three types of tests. The LCD screen is connected to the main controller via an RS232 serial interface. The main controller provides 5~15V power to the LCD screen, which can display various information, including sent commands and various collected values, such as current, voltage, flow rate, and air pressure. The main controller has multiple analog-to-digital converters (AD), digital-to-analog converters (DA), and I / O interfaces. I / O is used to send commands; AD collects current, voltage, flow rate, and air pressure data and performs digital-to-analog conversion; DA performs analog-to-digital conversion and sends signals. The test modules include insulation / withstand voltage / continuity testing modules, temperature measurement modules, and gas relay testing modules.

[0008] The insulation / withstand voltage / continuity test module is a module that can test insulation performance, withstand voltage performance, and continuity performance. These three aspects cannot be tested simultaneously; therefore, they are related as an OR condition. The insulation / withstand voltage / continuity test module includes a DC high-voltage module, a boost section, high-voltage relay I, high-voltage relay II, a high-voltage signal conditioning module, a current signal conditioning module, and multiple insulation / withstand voltage / continuity test terminals. The insulation / withstand voltage / continuity test terminals also include a grounding terminal. The DC high-voltage module is used to test insulation and continuity performance, while the boost section is used to test withstand voltage performance. The boost section includes an AC power module and a power frequency transformer boost module. The AC power module outputs AC voltage to the power frequency transformer boost module. The AC power module and the DC high-voltage module are connected together to a digital-to-analog converter (DA) interface on the main controller. Here, the main controller issues commands through the DA port, giving a command to turn on one of the modules based on the performance to be tested. If insulation and continuity performance are being tested, the DC high-voltage module is turned on; if withstand voltage performance is being tested, the boost section is turned on. The DC high-voltage module and the boost section each have their corresponding switches, both located within high-voltage relay I. These switches are connected to high-voltage relay II, and then connected to individual insulation / withstand voltage / continuity test terminals via corresponding switches within high-voltage relay II. High-voltage relay II contains multiple pairs of high-voltage on switches and current acquisition switches. The high-voltage on switches provide high-voltage signals to the terminals, while the current acquisition switches connect each terminal to a current signal conditioning module to acquire the corresponding current signal. Based on this current signal, the insulation / withstand voltage / continuity performance of the transformer is determined. Both the high-voltage on / off switch and the current acquisition switch are controlled by a drive circuit. Each pair of high-voltage on / off switches and current acquisition switches is connected in series with each corresponding insulation / withstand voltage / continuity test terminal. Typically, during testing, two terminals are inserted: one terminal provides a high-voltage signal, activating the high-voltage on / off switch at that terminal; the other terminal activates the current acquisition switch, and the acquired current signal is input to the analog-to-digital converter (AD) interface of the main controller. All high-voltage on / off switches are connected in parallel and then in series with high-voltage relay I; all current acquisition switches are connected in parallel and then in series with the current signal conditioning module. The current signal conditioning module is standard; its input signal is sent to the AD interface of the main controller, and the grounding terminal is also connected in series with the current signal conditioning module. The operation of the insulation / withstand voltage / continuity test module is as follows:

[0009] ① Insulation Testing Process: During insulation testing, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a high-voltage signal. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller, where it is displayed on the LCD screen. The high-voltage signal is typically several kilovolts or even higher. During testing, the high-voltage signal is usually maintained for a period of time, such as 10 minutes or more. During this time, the high-voltage signal conditioning module also inputs the voltage value to the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. If the current value remains below a certain threshold, it indicates that the transformer is working normally and the insulation performance is normal. If it exceeds a certain threshold, it indicates that the transformer is not working properly and the insulation performance is abnormal.

[0010] ② Withstand Voltage Testing Process: During the withstand voltage test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the AC power module via the DA port, causing AC power to be input to the power frequency transformer step-up module, gradually increasing the voltage in a stepped manner. Each voltage signal is maintained for one to two minutes. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. Current then flows through the current acquisition switch and passes through the current signal conditioning module. The voltage is input to the main controller's AD interface and displayed on the LCD screen. The high-voltage signal is typically several kilovolts, rising with a certain tolerance. During testing, the high-voltage signal is usually held for a period of time, such as 1-2 minutes, before continuing to rise. During this holding time, the high-voltage signal conditioning module also inputs the voltage value to the main controller via the AD interface. The current and voltage values ​​on the LCD screen are observed. If the current value remains below a certain threshold, it indicates that the transformer is working normally and its withstand voltage performance is normal. If it exceeds a certain threshold, it indicates that the transformer is malfunctioning and its insulation performance is abnormal. This testing process is used to test AC withstand voltage performance, and the voltage used is within the safe range (only withstand voltage performance testing is performed, not breakdown testing).

[0011] ③ Continuity Detection Process: When performing a continuity test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a certain voltage signal. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller, where it is displayed on the LCD screen. A certain voltage signal is sufficient to make the circuit conduct. The high-voltage signal conditioning module inputs the voltage value at this time into the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. When the current value is always present, it indicates continuity. If there is no current value, i.e., the current value is 0, it indicates non-conduction.

[0012] The temperature measurement module includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal and the current signal conditioning module are connected in series, and the input signal is sent to the analog-to-digital converter (AD) interface of the main controller. Since a temperature range of 160°C can be reflected by an electrical signal of 4~20mA in common temperature detection, this invention converts the temperature signal inside the transformer into an electrical signal by a thermistor. After passing through the current signal conditioning module, the signal is input to the analog-to-digital converter (AD) interface of the main controller, and then after conversion, it is displayed on the LCD screen to intuitively show the temperature value inside the transformer.

[0013] The gas relay testing module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller to control the opening and closing of the inert gas tank. The venting solenoid valve is controlled by another I / O interface of the main controller to control the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer. The flow sensor and pressure sensor are located on the gas path of the inert gas tank. The flow sensor and pressure sensor respectively input signals to two different analog-to-digital converter (AD) interfaces on the main controller. Specifically, when it is necessary to test whether the gas switch inside the transformer can operate normally, the I / O port outputs a command to open both the solenoid valve and the venting solenoid valve, allowing inert gas to be output from the gas tank into the transformer. The flow sensor and pressure sensor collect the flow rate and pressure signals, input from the AD interface, and after conversion, display the flow rate and pressure on the LCD screen. If the gas switch inside the transformer can operate normally after inputting a certain gas pressure, it means that it is working normally; otherwise, according to the normal gas pressure inside the transformer, the gas switch cannot operate normally, indicating an abnormal operation.

[0014] Preferably, the charging power source is a lithium polymer battery, which uses an AC mains input of 220V voltage and is converted into 12V DC voltage by an AC-DC converter to charge the lithium polymer battery.

[0015] Preferably, the input current of the temperature setting current input terminal is an electrical signal of 4~20mA, which can reflect a temperature range of 160℃.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The comprehensive testing and calibration instrument for transformer non-electrical quantity protection devices provided by the present invention (1) accurately realizes the non-electrical quantity detection of transformers, and provides assistance for the daily maintenance of transformers; (2) is integrated, realizes channel reuse, so that one device can realize multiple functions; (3) is designed to be portable, so as to be more convenient in actual use; (4) solves the problem that the non-electrical quantity protection devices of transformers are numerous and the product structures of various manufacturers are different, which makes the verification and testing of non-electrical quantity devices cumbersome and difficult to standardize; (5) realizes the comprehensive verification items such as insulation resistance test and withstand voltage test of secondary cables and terminals of non-electrical quantity protection devices, node operation test and some special performance tests, which can not only improve the test accuracy, but also simplify the verification steps, thereby greatly shortening the verification work time while ensuring the verification quality of non-electrical quantity devices; (6) It solves the problem of complicated wiring work, and the testing work is accurate, simple, time-saving and labor-saving; it directly reflects the electrical signal as a temperature signal, saving the trouble of calculation and making it easy to read; in addition, it can use different calculation formulas according to different temperature detection device models, and can control the input of appropriate gas to the transformer, and control its pressure and volume, thereby testing the reliable operation of the transformer's gas relay. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the module of the present invention.

[0018] Figure 2 This is a schematic diagram of the control interface of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments.

[0020] A comprehensive testing and calibration instrument suitable for non-electrical protection devices of transformers, such as Figure 1The system includes a central processing unit (CPU), signal conditioning and sampling circuits, a drive circuit, a display circuit, a clock circuit, a communication circuit, and a power supply. The CPU includes a main controller. The signal conditioning and sampling circuits include multiple analog-to-digital (A / D) converters, digital-to-analog (DA) converters, current signal conditioning modules, and voltage signal conditioning modules. The display circuit includes an LCD screen. All circuits are connected via communication circuits. The power supply is a rechargeable power supply. The main controller is connected to multiple test modules via the signal conditioning and sampling circuits. The LCD screen is connected to the main controller via an RS232 serial interface. The main controller provides 5-15V power to the LCD screen. The main controller contains multiple analog-to-digital converters (A / D) and digital-to-analog (DA) converters. The system includes an AD conversion interface, a DA conversion interface, and an I / O interface. The test module comprises an insulation / withstand voltage / continuity test module, a temperature measurement module, and a gas relay test module. The insulation / withstand voltage / continuity test module includes a DC high-voltage module, a boost section, a high-voltage relay I, a high-voltage relay II, a high-voltage signal conditioning module, a current signal conditioning module, and multiple insulation / withstand voltage / continuity test terminals. Each insulation / withstand voltage / continuity test terminal also includes a grounding terminal. The boost section includes an AC power module and a power frequency transformer boost module. The AC power module outputs AC voltage to the power frequency transformer boost module. The AC power module and the DC high-voltage module are connected together to a DA conversion interface on the main controller. The high-voltage relay I contains two switches. The DC high-voltage module and the power frequency transformer boost module are respectively connected to the high-voltage relay II through corresponding switches in the high-voltage relay I. The high-voltage relay II contains multiple pairs of high-voltage conduction switches and current acquisition switches. Both the high-voltage conduction switches and current acquisition switches are controlled by a drive circuit. Each pair of high-voltage conduction switches and current acquisition switches is connected in series with each insulation / withstand voltage / continuity test terminal except for the grounding terminal. All high-voltage conduction switches are connected in parallel and then in series with the high-voltage relay I. All current acquisition switches are connected in parallel and then in series with the current signal conditioning module. The current signal conditioning module inputs a signal to the analog-to-digital converter (AD) interface of the main controller. The grounding terminal is directly... The temperature measurement module is connected to the current signal conditioning module. It includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal and the current signal conditioning module are connected in series, and the input signal is sent to the analog-to-digital converter (AD) interface of the main controller. The gas relay testing module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller, and the venting solenoid valve is controlled by another I / O interface of the main controller. The solenoid valve controls the opening and closing of the inert gas tank, and the venting solenoid valve controls the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer, and the flow sensor and pressure sensor are located on the gas path of the inert gas tank.The flow sensor and pressure sensor respectively input signals to two different analog-to-digital converters (AD) on the main controller.

[0021] In this embodiment: the charging power supply is a lithium polymer battery, which is converted from 220V AC mains voltage to 12V DC voltage by an AC-DC converter to charge the lithium polymer battery; the input current of the temperature setting current input terminal is an electrical signal of 4~20mA; the main controller adopts the core board of HDSP-CORE28377D; the AC power module adopts an external AC power supply; and there are ten insulation / withstand voltage / continuity test terminals. The comprehensive testing and calibration instrument is controlled by a software system, which includes a main program module, a display module, an LCD keyboard scanning module, an A / D conversion module, and a digital filtering module. The main program module first initializes the entire control system, including main program initialization, serial port initialization, timer interrupt initialization, watchdog initialization, and A / D conversion initialization. After initialization, it enters normal data acquisition. Then, it displays and processes the acquired data, issuing control commands through control algorithms. During this process, the main program always responds to interrupt requests from other control subroutines. If an interrupt request is received, it is processed according to the interrupt priority. The display module displays system setpoints, real-time values, and operating status. The system calls the display module once per second to display real-time data. The LCD keyboard scanning module uses a polling method to receive information from the touchscreen. The A / D conversion module selects an A / D conversion chip based on the system requirements to convert the conditioned analog signal into a digital signal that the microcontroller can process. The digital filtering module performs a Fourier transform in each cycle, and then performs median averaging filtering on the transformed result to obtain the real-time value for that second.

[0022] The comprehensive testing and calibration instrument for transformer non-electrical protection devices provided in this embodiment has a panel as shown in the image. Figure 2 As shown, the detection process includes the following steps:

[0023] First, the process involves testing insulation, withstand voltage, and continuity.

[0024] ① Insulation Testing Process: During insulation testing, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a high-voltage signal. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller, where it is displayed on the LCD screen. The high-voltage signal is typically several kilovolts or even higher. During testing, the high-voltage signal is usually maintained for a period of time, such as 10 minutes or more. During this time, the high-voltage signal conditioning module also inputs the voltage value to the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. If the current value remains below a certain threshold, it indicates that the transformer is working normally and the insulation performance is normal. If it exceeds a certain threshold, it indicates that the transformer is not working properly and the insulation performance is abnormal.

[0025] ② Withstand Voltage Testing Process: During the withstand voltage test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the AC power module via the DA port, causing AC power to be input to the power frequency transformer step-up module, gradually increasing the voltage in a stepped manner. Each voltage signal is maintained for one to two minutes. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. Current then flows through the current acquisition switch and passes through the current signal conditioning module. The voltage is input to the main controller's AD interface and displayed on the LCD screen. The high-voltage signal is typically several kilovolts, rising with a certain tolerance. During testing, the high-voltage signal is usually held for a period of time, such as 1-2 minutes, before continuing to rise. During this holding time, the high-voltage signal conditioning module also inputs the voltage value to the main controller via the AD interface. The current and voltage values ​​on the LCD screen are observed. If the current value remains below a certain threshold, it indicates that the transformer is working normally and its withstand voltage performance is normal. If it exceeds a certain threshold, it indicates that the transformer is malfunctioning and its insulation performance is abnormal. This testing process is used to test AC withstand voltage performance, and the voltage used is within the safe range (only withstand voltage performance testing is performed, not breakdown testing).

[0026] ③ Continuity Detection Process: When performing a continuity test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a certain voltage signal. Simultaneously, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller, where it is displayed on the LCD screen. A certain voltage signal is sufficient to make the circuit conduct. The high-voltage signal conditioning module inputs the voltage value at this time into the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. When the current value is always present, it indicates continuity. If there is no current value, i.e., the current value is 0, it indicates non-conduction.

[0027] II. The temperature measurement module includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal and the current signal conditioning module are connected in series, and the input signal is sent to the analog-to-digital converter (AD) interface of the main controller. Since a temperature range of 160°C can be reflected by an electrical signal of 4~20mA in common temperature detection, this invention converts the temperature signal inside the transformer into an electrical signal by a thermistor. After passing through the current signal conditioning module, the signal is input to the analog-to-digital converter (AD) interface of the main controller, and then after conversion, it is displayed on the LCD screen to intuitively show the temperature value inside the transformer.

[0028] III. The gas relay test module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller to control the opening and closing of the inert gas tank. The venting solenoid valve is controlled by another I / O interface of the main controller to control the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer. The flow sensor and pressure sensor are located on the gas path of the inert gas tank. The flow sensor and pressure sensor respectively input signals to two different analog-to-digital converter (AD) interfaces on the main controller. Specifically, when it is necessary to test whether the gas switch inside the transformer can operate normally, the I / O port outputs a command to open both the solenoid valve and the venting solenoid valve, allowing inert gas to be output from the gas tank into the transformer. The flow sensor and pressure sensor collect the flow rate and pressure signals, input from the AD interface, and after conversion, display the flow rate and pressure on the LCD screen. If the gas switch inside the transformer can operate normally after inputting a certain gas pressure, it means that it is working normally; otherwise, according to the normal gas pressure inside the transformer, the gas switch cannot operate normally, indicating an abnormal operation.

[0029] The scope of protection claimed by this invention is not limited to the specific embodiments described above. Moreover, for those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A comprehensive detection calibrator for non-electric quantity protection device of transformer, characterized in that: It includes a central processing unit, signal conditioning and sampling circuits, drive circuits, display circuits, clock circuits, communication circuits, and a power supply. The central processing unit includes a main controller. The signal conditioning and sampling circuits include multiple analog-to-digital converters (AD), digital-to-analog converters (DA), current signal conditioning modules, and voltage signal conditioning modules. The display circuit includes a liquid crystal display screen. All circuits are connected to each other via communication circuits. The power supply is a rechargeable power supply. ​ The main controller is connected to multiple test modules via signal conditioning and sampling circuits. The LCD screen is connected to the main controller via an RS232 serial interface. The main controller provides a 5-15V power supply to the LCD screen. The main controller has multiple analog-to-digital converters (AD), digital-to-analog converters (DA), and I / O interfaces. The test modules include an insulation / withstand voltage / continuity test module, a temperature measurement module, and a gas relay test module. The insulation / withstand voltage / continuity test module includes a DC high-voltage module, a boost section, high-voltage relay I, high-voltage relay II, a high-voltage signal conditioning module, a current signal conditioning module, and multiple insulation / withstand voltage / continuity test terminals. Each insulation / withstand voltage / continuity test terminal also includes a grounding terminal. The boost section includes an AC power module and a power frequency transformer boost module. The AC power module outputs AC voltage to the power frequency transformer boost module. The AC power module and the DC high-voltage module are connected together to a digital-to-analog converter (DA) interface of the main controller. The high-voltage relay I contains two switches. The DC high-voltage module and the power frequency transformer boost module... The modules are connected to high-voltage relays II via corresponding switches within high-voltage relay I. High-voltage relay II contains multiple pairs of high-voltage on-state switches and current acquisition switches, all controlled by a drive circuit. Each pair of high-voltage on-state switches and current acquisition switches is connected in series with each insulation / withstand voltage / continuity test terminal (excluding the grounding terminal). All high-voltage on-state switches are connected in parallel and then in series with high-voltage relay I. All current acquisition switches are connected in parallel and then in series with the current signal conditioning module. The current signal conditioning module inputs a signal to the analog-to-digital converter (AD) interface of the main controller. The grounding terminal is directly connected to the current signal conditioning module. The temperature measurement module includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal and the current signal conditioning module are connected in series and the input signal is given to the analog-to-digital conversion interface (AD) of the main controller. The gas relay test module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller, and the venting solenoid valve is controlled by another I / O interface of the main controller. The solenoid valve controls the opening and closing of the inert gas tank, and the venting solenoid valve controls the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer. The flow sensor and pressure sensor are located on the gas path of the inert gas tank. The flow sensor and pressure sensor respectively input signals to two different analog-to-digital converter interfaces (AD) on the main controller. The comprehensive testing and calibration instrument is controlled by a software system, which includes a main program module, a display module, an LCD keyboard scanning module, an A / D conversion module, and a digital filtering module. Main program module: First, it initializes the entire control system, including main program initialization, serial port initialization, timer interrupt initialization, watchdog initialization, and A / D conversion initialization. After initialization, it enters normal data acquisition. Then, it displays and processes the acquired data and issues control commands through the control algorithm. During this process, the main program always responds to interrupt requests from other control subroutines. If there is an interrupt request, it transfers to the corresponding processing program according to the interrupt priority. Display module: The display subroutine function group is responsible for displaying system setpoints, real-time values, and working status. The system calls the display module once per second to display real-time system data. LCD keyboard scanning module: The LCD keyboard scanning uses a query method to receive information transmitted from the touch screen; A / D conversion module: Select an A / D conversion chip according to the requirements of the whole system to convert the conditioned analog signal into a digital signal that can be processed by the microcontroller; Digital filtering module: Performs Fourier transform in each cycle, and then performs median averaging filtering on the transformed result to obtain the real-time value for that second; The testing process includes the following steps: First, the process involves testing insulation, withstand voltage, and continuity. ① Insulation testing process: When performing insulation testing, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a high-voltage signal. At the same time, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller, and is displayed on the LCD screen. During the test, the high-voltage signal is held for a period of time. During this time, the high-voltage signal conditioning module also inputs the voltage value at this time into the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. When the current value is consistently below a certain threshold, it indicates that the transformer is working normally and the insulation performance is normal. If it is above a certain threshold, it indicates that the transformer is not working properly and the insulation performance is abnormal. ② Withstand Voltage Test Process: When performing a withstand voltage test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the AC power module through the DA port, allowing AC power to be input into the power frequency transformer step-up module. The voltage is gradually increased in a step-like manner, and each voltage signal is held for one to two minutes. At the same time, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, the current signal conditioning module, and enters the AD interface of the main controller. The current is displayed on the LCD screen. The high-voltage signal rises with a certain tolerance value. During the test, the high-voltage signal is held for a period of time before continuing to rise. During the holding time, the high-voltage signal conditioning module also inputs the voltage value at this time into the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. When the current value is consistently below a certain threshold, it indicates that the transformer is working normally and the withstand voltage performance is normal. If it is above a certain threshold, it indicates that the transformer is not working properly and the insulation performance is also abnormal. ③ Continuity Detection Process: When performing a continuity test, connect two insulation / withstand voltage / continuity test terminals or grounding terminals. The main controller sends a signal to the DC high-voltage module through the DA port, outputting a certain voltage signal. At the same time, the corresponding switch in high-voltage relay I is turned on. The main controller closes the high-voltage conduction switch of one test terminal in high-voltage relay II and the current acquisition switch of the other test terminal. The current then passes through the current acquisition switch, enters the AD interface of the main controller through the current signal conditioning module, and is displayed on the LCD screen. A certain voltage signal is sufficient to make the circuit conduct. The high-voltage signal conditioning module inputs the voltage value at this time into the main controller through the AD interface. Observe the current and voltage values ​​on the LCD screen. When the current value is always present, it means that the circuit is conducting. If there is no current value, that is, the current value is 0, it means that the circuit is not conducting. II. The temperature measurement module includes a temperature setting current input terminal and a current signal conditioning module. The temperature setting current input terminal and the current signal conditioning module are connected in series and the input signal is sent to the analog-to-digital converter (AD) interface of the main controller. This allows the temperature signal inside the transformer to be converted into an electrical signal by the thermistor. After passing through the current signal conditioning module, the signal is sent to the analog-to-digital converter (AD) interface of the main controller, and then after conversion, it is displayed on the LCD screen to intuitively show the temperature value inside the transformer. III. The gas relay testing module includes an inert gas tank, a solenoid valve, a venting solenoid valve, a flow sensor, and a pressure sensor. The solenoid valve is controlled by one I / O interface of the main controller to control the opening and closing of the inert gas tank. The venting solenoid valve is controlled by another I / O interface of the main controller to control the gas flow rate. The gas path of the inert gas tank is connected to the gas interface of the transformer. The flow sensor and pressure sensor are located on the gas path of the inert gas tank. The flow sensor and pressure sensor respectively input signals to two different analog-to-digital converter (AD) interfaces on the main controller. Specifically, when it is necessary to test whether the gas switch in the transformer can operate normally, the I / O port outputs a command to open both the solenoid valve and the venting solenoid valve, allowing inert gas to be output from the gas tank into the transformer. The flow sensor and pressure sensor collect the flow rate and pressure signals, input from the AD interface, and after conversion, display the flow rate and pressure on the LCD screen. If the gas switch in the transformer can operate normally after a certain gas pressure is input, it means that it is working normally. Otherwise, according to the normal gas pressure in the transformer, the gas switch cannot operate normally, which means that it is malfunctioning.

2. The integrated detection and calibration instrument for non-electric quantity protection device of transformer according to claim 1, characterized in that: The charging power source is a lithium polymer battery. It uses 220V AC mains input voltage, which is converted into 12V DC by an AC-DC converter to charge the lithium polymer battery.

3. The comprehensive testing and calibration instrument for transformer non-electrical protection devices according to claim 1, characterized in that: The temperature setting current input terminal receives an electrical signal of 4~20mA.

4. A comprehensive testing and calibration instrument for transformer non-electrical quantity protection devices according to claim 1, characterized in that: The main controller uses the HDSP-CORE28377D core board.

5. A comprehensive testing and calibration instrument for transformer non-electrical quantity protection devices according to claim 1, characterized in that: The AC power module uses an external AC power supply.

6. A comprehensive testing and calibration instrument for transformer non-electrical quantity protection devices according to claim 1, characterized in that: The insulation / withstand voltage / continuity test terminals are provided in ten locations.

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