Wired Zinc Oxide Arrester Resistive Current Tester
Product Features
1. High current carrying capacity
This is mainly reflected in the arrester's ability to absorb various lightning overvoltages, power frequency transient overvoltages, and switching overvoltages. The current carrying capacity 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 carrying capacity 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 blocks are excellent, only a few hundred microamperes of current pass through under normal operating voltage, making it easy to design with a gapless structure, which gives it the characteristics of good protection performance, light weight, and small size. When overvoltage intrudes, the current through the valve block increases rapidly, while limiting the amplitude of the overvoltage and releasing the energy of the overvoltage. After that, the zinc oxide valve block returns to a high resistance state, allowing the power system to operate normally.
3. Good sealing performance
The arrester components use high-quality composite housings with good aging resistance and air tightness. Measures such as controlling the compression of sealing rings and applying additional sealant are adopted, with ceramic housing as the sealing material, ensuring reliable sealing and stable performance of the arrester.
4. Mechanical performance
Mainly consider the following three factors:
(1) The seismic force it can withstand;
(2) The maximum wind pressure acting on the arrester;
(3) The maximum allowable tensile force of the conductor exerted on the top of the arrester.
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 Very 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 product quality is mainly affected by the following three aspects:
(1) The rationality of the overall structure of the arrester;
(2) The volt-ampere characteristics and aging resistance of the zinc oxide valve blocks;
(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", 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 select, after all positions are adjusted, press "OK".
l PT ratio: Press the "Function" key to move the cursor to "PT ratio", press "OK" to enter; press the "Function" key to select the position you want to adjust, and a small cursor will appear at this position; then press the "Increase" and "Decrease" keys to select, after the position adjustment is completed, press "OK".
l Test phase sequence: Press the "Function" key to move the cursor to "Test phase sequence", press "OK" to enter; press the "Function" key to select the position you want to adjust, and a small cursor will appear at this position; press the "Increase" and "Decrease" keys to select, after the position adjustment is completed, press "OK". 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°~5°. Since it is difficult to accurately calculate the interference amount, hard compensation is generally not recommended, but it is set to 0.0°. According to regulations, the data trend over a period of time can be compared longitudinally. If you need to adjust the edge phase correction angle, refer to the relevant section of "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 "OK".
l Mode: Press "OK" to switch among wired, induction, and wireless modes.
l View: Press the "Function" key to move the cursor to "View", 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", press "OK" to enter measurement, and the measurement screen as shown in Figure 7 appears.
Display: Switch the display screen to show all test information or a brief display. If it is three-phase simultaneous measurement, press "Increase" and "Decrease" to cyclically display 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 data communication packaging software provided with the instrument on the computer, and use a serial communication line to connect the instrument to the RS-232 serial port of the computer. Turn on the instrument power, run the communication program on the computer, click the desired function on the computer, and the relevant operation can be completed.
Product Introduction
An arrester with good protective performance. Utilizing the good nonlinear volt-ampere characteristics of zinc oxide, the current flowing through the arrester is extremely small (microampere or milliampere level) during 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 perform the functions of current discharge and interruption.
