Special environment weather resistance test device and test method for on-line monitoring current sensor

Abstract

The invention discloses a special environment weather resistance test device and test method for monitoring a current sensor on line, and belongs to the technical field of current sensor tests.The device comprises a test box, a test tool and an excitation output source, the test tool is arranged on the upper portion in the test box, and an ultraviolet lamp array is arranged on the lower portion in the test box; the excitation output source is arranged on the top surface of the test box, and the excitation output source is connected with the two ends of the test tool. A special excitation circuit is additionally arranged outside the test box, and a sensor test tool is designed in the test box, so that various performance tests of sensitivity, dynamic range, linearity error and the like of current sensors of various models can be carried out under the extreme environment condition that the current sensors are always in the environment weather-proof test box.

Description

Technical Field

[0001] The present invention relates to the technical field of current sensor testing, in particular to a special environmental weathering resistance testing device and a testing method for an online monitoring current sensor. Background Art

[0002] With the rapid development of digital and intelligent power grids, the number and types of online monitoring devices for transformers, such as high-frequency partial discharge (PD) and core / clamp grounding current, are increasing. However, since the current sensors in these online monitoring devices are installed outdoors, they are exposed to extreme high and low temperatures, high humidity, and UV radiation for long periods of time. This can lead to key performance issues such as reduced sensor sensitivity, insufficient dynamic range, or excessive linearity errors. These issues hinder the accurate assessment of transformer operating conditions. Therefore, environmental weathering testing is required before finalizing each model of current sensor to ensure reliable long-term weathering performance. The current testing method involves placing the sensor in an environmental weathering chamber, setting the environmental conditions, and then removing the sensor for various performance tests. This testing method introduces uncertainty regarding the potential for performance rebound due to environmental changes after the sensor is removed. The ideal testing method is to maintain the sensor in extreme environments for performance testing. Therefore, a dedicated environmental weathering test device and testing method for current sensors in online monitoring devices is needed. Summary of the Invention

[0003] In view of this, the present invention addresses the deficiencies in the prior art and provides a dedicated environmental weathering test device and test method for an online monitoring current sensor.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a special environmental weathering test device for online monitoring current sensors, including a test box, a test tool and an excitation output source, the test tool is arranged in the upper part of the test box, the ultraviolet lamp array is arranged in the lower part, and a humidifier and a heater are arranged on the side, the excitation output source is arranged on the top surface of the test box, and the excitation output source is connected to both ends of the test tool.

[0005] Furthermore, the test chamber is provided with a control module, which includes a temperature rise control logic circuit, a relative humidity control logic circuit, an ultraviolet intensity control logic circuit and a time control logic circuit. The temperature rise control logic circuit is connected to the heater signal, the relative humidity control logic circuit is connected to the humidifier signal, and the ultraviolet intensity control logic circuit is connected to the ultraviolet lamp array signal.

[0006] Furthermore, the test tool is a copper rod with a diameter of 1 cm.

[0007] Furthermore, the excitation output source is a function generator, which can output two types of signals: high-frequency current and industrial frequency current.

[0008] Furthermore, multiple test wires are installed on both sides of the test box, one end of the test wire is inside the test box and connected to the current sensor, and the other end of the test wire is outside the test box and connected to the current sensor response background.

[0009] Furthermore, a device start main switch, a temperature control switch, a humidity control switch and an ultraviolet control switch are provided on the front panel of the test box.

[0010] Furthermore, a temperature adjustment knob, a humidity adjustment knob and an ultraviolet irradiation intensity adjustment knob are provided on the front panel of the test box.

[0011] Furthermore, the front panel of the test box is provided with a real-time temperature display inside the box, a real-time relative humidity display inside the box, a real-time ultraviolet intensity display inside the box and a test timing display.

[0012] Furthermore, an observation window is provided on the front panel of the test box.

[0013] Furthermore, the test method of the dedicated environmental weathering test device for online monitoring current sensor comprises the following steps: Step 1: Open the door of the test box, connect multiple current sensors to be tested to the test wires in the box, connect the other ends of the test wires to the current sensor response background, and connect the two ends of the test tool to the excitation output source through signal lines; after all wiring work is completed, close the door and fasten it with a lock to ensure good sealing; Step 2: Start the excitation output source and output a series of excitation signals to perform sensitivity test, dynamic range test, and linearity error test before the weather resistance test of the current sensor; Sensitivity test: adjust the excitation signal to increase slowly from 0, and record the sensitivity value when the response value of the current sensor just exceeds 2 times the background value; Dynamic range test: Continue to increase the excitation signal slowly and evenly, record the response value of the current sensor under test at different test points, and determine whether the dynamic range meets the "sensitivity + 40dB" requirement; Linearity error test: Take the value of "sensitivity + 40dB" as the dynamic range reference value, take the test data corresponding to the reference points of 80%, 60%, 40%, and 20% of the reference value to carry out linearity error analysis and calculation. The maximum allowable linearity error shall not exceed the value specified in the standard; Step 3: Start the main switch of the device on the test box, select and start the temperature control switch, humidity control switch, and UV control switch according to the test requirements of the environmental weathering test, and use the temperature adjustment knob, humidity adjustment knob, and UV intensity adjustment knob to control the parameters; observe the real-time temperature display, real-time relative humidity display, and real-time UV intensity display in the box to judge the environmental status in the box. After the environmental conditions in the box meet the test requirements, maintain the box status and start the test timing function at the same time; Step 4: After the current sensor meets the test time requirements under the environmental conditions in the box, the excitation output source is started again to carry out the current sensor sensitivity test, dynamic range test, and linearity error test, and record and analyze whether there are any differences in various indicators.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention designs a set of special environmental weathering test equipment. By adding a special excitation circuit to the outside of the test box and designing sensor testing tooling inside the test box, various types of current sensors can be tested for various performance such as sensitivity, dynamic range, and linearity error under extreme environmental conditions in the environmental weathering test box. It can meet the weathering test of current sensors of two different types of online monitoring devices, industrial frequency and high frequency. It can simultaneously carry out weathering tests on more than 6 current sensors at a time. The test efficiency is high and the operation safety is high, which is very valuable for promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of Example 1 of the present invention when the door is closed; Figure 2 This is a schematic structural diagram of Example 1 of the present invention with the door open; Figure 3 It is a schematic diagram of the partial structure of Example 2 of the present invention; Figure 4 Schematic diagram of the structure of the test tool in Example 2 of the present invention; Figure 5 is a cross-sectional view of the test fixture in Example 2 of the present invention; In the figure: 1-test chamber, 2-test fixture, 3-excitation output source, 4-UV lamp array, 5-humidifier, 6-heater, 7-AC power plug, 8-temperature rise control logic circuit, 9-relative humidity control logic circuit, 10-UV intensity control logic circuit, 11-time control logic circuit, 12-test line, 13-current sensor, 14-device start main switch, 15-temperature control switch, 16-humidity control switch, 17-UV control switch, 18-temperature adjustment knob, 19-humidity adjustment knob, 20-UV irradiation intensity adjustment knob, 21-real-time temperature display inside the chamber, 22-real-time relative humidity display inside the chamber, 23-real-time UV intensity display inside the chamber, 24-test timing display, 25-observation window, 26-lock buckle, 27-through-type current sensor, 201-copper rod, 202-first copper connector, 203-handwheel, 204-second copper connector, 205-blind hole. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0017] Example 1: Figures 1 and 2 As shown, a special environmental weathering test device for online monitoring current sensors includes a test box 1, a test fixture 2 and an excitation output source 3. The test fixture 2 is set in the upper part of the test box 1, the ultraviolet lamp array 4 is set in the lower part, and a humidifier 5 and a heater 6 are set on the side. The heater 6 is a thermal resistance wire array. The excitation output source 3 is set on the top surface of the test box 1. The excitation output source 3 is connected to both ends of the test fixture 2. An AC power plug 7 is set on the back side of the test box 1.

[0018] Specifically, the test box 1 is provided with a control module, which includes a temperature rise control logic circuit 8, a relative humidity control logic circuit 9, an ultraviolet intensity control logic circuit 10 and a time control logic circuit 11. The temperature rise control logic circuit 8 is connected to the heater 6 signal, which can meet the simulation scenes under different ambient temperature parameters in the box; the relative humidity control logic circuit 9 is connected to the humidifier 5 signal, which can meet the simulation scenes under different ambient humidity parameters in the box; the ultraviolet intensity control logic circuit 10 is connected to the ultraviolet lamp array 4 signal, which can meet the simulation scenes under different ultraviolet irradiation parameters in the box.

[0019] The test fixture 2 is a copper rod with a diameter of 1 cm, which is placed horizontally and passes through the inner walls on both sides of the test box 1, and can meet the requirements of the inner diameter of most current transformers on the market.

[0020] The excitation output source 3 is a function generator that can output two types of signals: high-frequency current and industrial frequency current. According to the requirements of its internal controller module, the function generator outputs various current excitation signals with different amplitudes and different frequency parameters.

[0021] Three test wires 12 are installed on both sides of the test box 1. One end of the test wire 12 is inside the test box 1 and connected to the current sensor 13. The other end of the test wire 12 is outside the test box 1 and connected to the current sensor response background.

[0022] The front panel of the test box 1 is provided with a device start main switch 14, a temperature control switch 15, a humidity control switch 16 and a UV control switch 17, which can satisfy the function of the tester to select any single environmental simulation scene or a combination of multiple scenes.

[0023] The front panel of the test box 1 is provided with a temperature adjustment knob 18, a humidity adjustment knob 19 and an ultraviolet irradiation intensity adjustment knob 20, which can satisfy the test personnel to select specific parameters of each environmental simulation scene.

[0024] The front panel of the test chamber 1 is provided with a real-time temperature display 21, a real-time relative humidity display 22, and a real-time UV intensity display 23, which can help testers understand the real-time status of the simulated environmental scene inside the chamber. Furthermore, a test timer display 24 is also provided on the front panel, which can help testers understand the cumulative test time of the environmental weather resistance test.

[0025] An observation window 25 is provided on the front panel of the test box 1 to allow test personnel to observe the arrangement of the internal current transformers.

[0026] The test method of the dedicated environmental weathering test device for online monitoring current sensors according to an embodiment of the present invention comprises the following specific steps: (1) Wiring before the test. Open the door of the test box 1 and connect the six current sensors 13 to be tested to the test wires 12 in the box. Since most current transformers on the market are open-type, the current sensors can be conveniently passed through the core and hung on the test fixture. The other end of the test wire 12 is connected to the current sensor response background. The two ends of the test fixture 2 are connected to the excitation output source 3 through signal lines. After all wiring work is completed, close the box door and fasten it with the lock 26 to ensure good sealing.

[0027] (2) Current sensor performance test before weather resistance test. Start the excitation output source 3 and output a series of excitation signals to perform various index tests such as sensitivity test, dynamic range test, linearity error test, etc. before the weather resistance test of the current sensor 13; Sensitivity test: adjust the excitation signal to increase slowly from 0, and record the sensitivity value when the response value of the current sensor 13 just exceeds 2 times the background value; Dynamic range test: Continue to increase the excitation signal slowly and evenly, record the response value of the current sensor under test at different test points, and determine whether the dynamic range meets the "sensitivity + 40dB" requirement; Linearity error test: Take the value of "sensitivity + 40dB" as the dynamic range reference value, and take the test data corresponding to the reference points of 80%, 60%, 40%, and 20% of the reference value to carry out linearity error analysis and calculation. The maximum allowable linearity error shall not exceed the value specified in the standard.

[0028] (3) Set the environmental conditions in the box. Start the main switch 14 of the device on the test box 1. According to the test requirements of the environmental weather resistance test, select to start the temperature control switch 15, humidity control switch 16, and UV control switch 17, and use the temperature adjustment knob 18, humidity adjustment knob 19, and UV intensity adjustment knob 20 to control the parameters; observe the real-time temperature display 21, the real-time relative humidity display 22, and the real-time UV intensity display 23 in the box to judge the environmental conditions in the box. After the environmental conditions in the box meet the test requirements, maintain the box status and start the test timing function at the same time.

[0029] (4) Current sensor performance test after weathering. After the current sensor 13 meets the test time requirements under the environmental conditions in the box, the excitation output source 3 is started again to carry out various index tests such as current sensor sensitivity test, dynamic range test, linearity error test, etc., and record and analyze whether there are any differences in each index.

[0030] By repeating this process, tests of different durations can be carried out to analyze the changing trends of the current sensor under different accelerated aging times.

[0031] Example 2: Figures 3-5 As shown, the dedicated environmental weathering test device for online monitoring current sensors according to the embodiment of the present invention is different from that of embodiment 1 in that: The test fixture includes a copper rod 201 and two copper connectors. The two copper connectors are respectively embedded in the inner walls of the test box 1 on both sides and are connected to the excitation output source 3. The two ends of the copper rod 201 are movably connected to the two copper connectors. The first copper connector 202 on the left is provided with a through hole with a thread inside the through hole. The left end of the copper rod 201 is provided with an external thread, which is threadedly connected to the first copper connector 202, and the left end of the copper rod 201 can extend from the first copper connector 202, and a handwheel 203 is provided at the end to facilitate the twisting of the copper rod 201; the second copper connector 204 on the right is provided with a blind hole 205, and the depth of the blind hole 205 matches the length of the thread on the copper rod 201, so that when the left end of the copper rod 201 is threadedly connected to the first copper connector 202, the right end of the copper rod 201 contacts the bottom surface of the blind hole 205.

[0032] Since the test fixture in Example 1 can only meet the requirements of the clamp-type current sensor test, in order to meet the requirements of the through-type current sensor 27 test, the test fixture used in the embodiment of the present invention includes a copper rod 201 and two copper connectors. The copper rod 201 is detachably connected to the two copper connectors. When installing the current sensor before the test, the left end of the copper rod 201 is twisted to disengage its threaded portion from the first copper connector 202, thereby pulling the copper rod 201 to the left for a certain distance, and then installing the current sensor to be tested from the right end of the copper rod 201. Thereafter, the right end of the copper rod 201 is inserted into the blind hole of the second copper connector 204, and the copper rod 201 is twisted in the opposite direction to be threadedly connected to the first copper connector 202. At this time, the right end of the copper rod 201 contacts the bottom surface of the blind hole 205 of the second copper connector 204, thereby reliably connecting the copper rod 201 to the two copper connectors to ensure the test effect.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field can still modify or replace the specific implementation methods of the present invention with equivalents. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention.

Claims

1. A dedicated environmental weathering test device for online monitoring current sensors, characterized by: It includes a test box, a test tool and an excitation output source. The test tool is set on the upper part of the test box, the ultraviolet lamp array is set on the lower part, and a humidifier and a heater are set on the side. The excitation output source is set on the top surface of the test box and is connected to both ends of the test tool.

2. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The test chamber is provided with a control module, which includes a temperature rise control logic circuit, a relative humidity control logic circuit, an ultraviolet intensity control logic circuit and a time control logic circuit. The temperature rise control logic circuit is connected to the heater signal, the relative humidity control logic circuit is connected to the humidifier signal, and the ultraviolet intensity control logic circuit is connected to the ultraviolet lamp array signal.

3. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The test fixture is a copper rod with a diameter of 1 cm.

4. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The excitation output source is a function generator, which can output two types of signals: high-frequency current and industrial frequency current.

5. The dedicated environmental weathering test device for online monitoring current sensor according to claim 1, characterized in that: A plurality of test lines are installed on both sides of the test box. One end of the test line is inside the test box and connected to the current sensor, and the other end of the test line is outside the test box and connected to the current sensor response background.

6. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The front panel of the test box is provided with a device start main switch, a temperature control switch, a humidity control switch and an ultraviolet control switch.

7. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The front panel of the test box is provided with a temperature adjustment knob, a humidity adjustment knob and an ultraviolet irradiation intensity adjustment knob.

8. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: The front panel of the test box is provided with a real-time temperature display inside the box, a real-time relative humidity display inside the box, a real-time ultraviolet intensity display inside the box and a test timing display.

9. The dedicated environmental weathering test device for online monitoring current sensors according to claim 1, characterized in that: An observation window is provided on the front panel of the test box.

10. The test method of the dedicated environmental weather resistance test device for online monitoring current sensor according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Open the door of the test box, connect multiple current sensors to be tested to the test wires in the box, connect the other ends of the test wires to the current sensor response background, and connect the two ends of the test tool to the excitation output source through signal lines; after all wiring work is completed, close the door and fasten it with a lock to ensure good sealing; Step 2: Start the excitation output source and output a series of excitation signals to perform sensitivity test, dynamic range test, and linearity error test before the weather resistance test of the current sensor; Sensitivity test: adjust the excitation signal to increase slowly from 0, and record the sensitivity value when the response value of the current sensor just exceeds 2 times the background value; Dynamic range test: Continue to increase the excitation signal slowly and evenly, record the response value of the current sensor under test at different test points, and determine whether the dynamic range meets the "sensitivity + 40dB" requirement; Linearity error test: Take the value of "sensitivity + 40dB" as the dynamic range reference value, and take the test data corresponding to the reference points of 80%, 60%, 40%, and 20% of this reference value to carry out linearity error analysis and calculation. The maximum allowable linearity error shall not exceed the value specified in the standard; Step 3: Start the main switch of the device on the test box, select and start the temperature control switch, humidity control switch, and UV control switch according to the test requirements of the environmental weathering test, and use the temperature adjustment knob, humidity adjustment knob, and UV intensity adjustment knob to control the parameters; observe the real-time temperature display, real-time relative humidity display, and real-time UV intensity display in the box to judge the environmental status in the box. After the environmental conditions in the box meet the test requirements, maintain the box status and start the test timing function at the same time; Step 4: After the current sensor meets the test time requirements under the environmental conditions in the box, the excitation output source is started again to carry out the current sensor sensitivity test, dynamic range test, and linearity error test, and record and analyze whether there are any differences in various indicators.

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