Wired Zinc Oxide Arrester Resistive Current Tester
Product Features
1. High current handling capability
This is mainly reflected in the arrester's ability to absorb various lightning overvoltages, power frequency transient overvoltages, and switching overvoltages. The current handling capability of zinc oxide arresters fully meets or even exceeds national standards. Indicators such as line discharge class, energy absorption capability, 4/10 nanosecond high current impulse withstand, and 2ms square wave current handling capability have reached the domestic leading level.
2. Excellent protective characteristics
Zinc oxide arresters are electrical products used to protect various electrical equipment in power systems from overvoltage damage, and they have good protective performance. Because the nonlinear volt-ampere characteristics of zinc oxide valve plates are excellent, only a few hundred microamperes of current pass through under normal operating voltage, making it easy to design a gapless structure, which gives it the characteristics of good protective performance, light weight, and small size. When overvoltage intrudes, the current flowing through the valve plate increases rapidly, while limiting the amplitude of the overvoltage and releasing the energy of the overvoltage. After that, the zinc oxide valve plate returns to a high-resistance state, allowing the power system to operate normally.
3. Good sealing performance
The arrester components use high-quality composite outer sheath with good aging resistance and airtightness, and adopt measures such as controlling the compression of sealing rings and applying additional sealant. The ceramic outer sheath is used as a sealing material to ensure reliable sealing and stable performance of the arrester.
4. Mechanical performance
Mainly consider the following three factors:
(1) Earthquake force it can withstand;
(2) Maximum wind pressure acting on the arrester;
(3) Maximum allowable tension of the conductor that the top of the arrester can bear.
5. Good anti-pollution performance
Gapless zinc oxide arresters have high pollution resistance.
The creepage distance ratio levels specified by national standards are:
Class II Medium pollution area: creepage distance ratio 20mm/kV
Class III Heavy pollution area: creepage distance ratio 25mm/kV
Class IV Extra heavy pollution area: creepage distance ratio 31mm/kV
6. High operational reliability
The reliability of long-term operation depends on the quality of the product and whether the product selection is reasonable. The factors affecting product quality mainly include the following three aspects:
(1) The rationality of the overall structure of the arrester;
(2) The volt-ampere characteristics and aging resistance of zinc oxide valve plates;
(3) The sealing performance of the arrester.
7. Power frequency withstand capability
Due to various reasons in the power system such as single-phase grounding, long-line capacitance effect, and load shedding, the power frequency voltage may rise or transient overvoltages with high amplitude may occur. The arrester has the ability to withstand a certain increase in power frequency voltage for a certain period of time.
Operating Steps
Turn on the power switch, and the startup screen appears.
After a few seconds, the main menu appears as shown below (figure). The specific operation instructions for the main menu are as follows:
l Line number: Press the "Function" key to move the cursor to "Line number", then press "OK" to enter; press the "Function" key to select the position to adjust, and a small cursor will appear at this position; press the "Increase" and "Decrease" keys to make selections. After all positions are adjusted, press the "OK" key.
l PT ratio: Press the "Function" key to move the cursor to "PT ratio", then press "OK" to enter; press the "Function" key to select the position to adjust, and a small cursor will appear at this position; then press the "Increase" and "Decrease" keys to make selections. After all positions are adjusted, press the "OK" key.
l Test phase sequence: Press the "Function" key to move the cursor to "Test phase sequence", then press "OK" to enter; press the "Function" key to select the position to adjust, and a small cursor will appear at this position; press the "Increase" and "Decrease" keys to make selections. After all positions are adjusted, press the "OK" key. Among them, A, B, C represent single-phase measurement, and X represents three-phase simultaneous measurement.
l Compensation angle: The adjustment method is the same as above. Generally, the influence of interphase interference is about 2° to 5°. Since it is difficult to accurately calculate the interference amount, hard compensation is generally not recommended; instead, it is set to 0.0°. According to regulations, the data change trend over a period of time can be compared longitudinally. If you need to adjust the side-phase correction angle, refer to the relevant sections in "Measurement Principle" later. If three-phase simultaneous measurement is selected, the angle is automatically compensated.
l Date: The adjustment method is the same as above. Use the "Function" key to select the item to adjust: year, month, day, hour, minute, second, and use the "Increase" and "Decrease" keys to adjust. After all adjustments are completed, press the "OK" key.
l Mode: Press "OK" to switch among wired, induction, and wireless modes.
l View: Press the "Function" key to move the cursor to "View", then press "OK" to enter (as shown in Figure 6); press the "Increase", "Decrease", and "Function" keys to select the data to view, and press "OK" to display that set of data.
l Measurement: Press the "Function" key to move the cursor to "Test", then press "OK" to enter measurement, and the measurement screen shown in Figure 7 appears.
Display: Switch the display screen to show all test information or a brief display. If three-phase simultaneous measurement is selected, press "Increase" and "Decrease" to cycle through the information of the three phases.
Print: Can print the measured data, but not store it.
Store: Store the current data. Select the storage location for the data and press "OK" to save.
Exit: Exit measurement and return to the system main menu.
7. Data upload: Install the accompanying data communication packaging software on the computer, and connect the instrument to the computer's RS-232 serial port with a serial communication cable. Turn on the instrument power, run the communication program on the computer, and click the desired function on the computer to complete the related operations.
Product Introduction
An arrester with good protective performance. Utilizing the excellent nonlinear volt-ampere characteristics of zinc oxide, the current flowing through the arrester is extremely small (microampere or milliampere level) under normal operating voltage; when overvoltage acts, the resistance drops sharply, releasing the energy of the overvoltage to achieve protection. The difference between this arrester and traditional arresters is that it has no discharge gap, and uses the nonlinear characteristics of zinc oxide to achieve current discharge and interruption.
Technical Parameters
Maximum output voltage: 35kV
Maximum output current: 1.2mA (at 30kV)
Maximum output power: 36W
Voltage ripple coefficient: 0.5%
Voltage measurement accuracy: ±0.5%
0.75 times voltage accuracy: 1%
1mA current accuracy: ±0.5%
Current measurement accuracy: ±0.5%
Power supply: AC 220V±15% or internal power supply
Operating temperature: 25±10℃
Dimensions and weight: 320mm×250mm×160mm, 5.5kg
