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 varistors 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 varistor increases rapidly, while limiting the amplitude of the overvoltage and releasing the energy of the overvoltage. After that, the zinc oxide varistor 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, and ceramic housings are used as sealing materials to ensure reliable sealing and stable performance of the arrester.
4. Mechanical performance
The following three factors are mainly considered:
(1) Earthquake force that may be withstood;
(2) Maximum wind pressure acting on the arrester;
(3) Maximum allowable tensile force of the conductor borne by the top of the arrester.
5. Good anti-pollution performance
Gapless zinc oxide arresters have high pollution resistance.
The specific creepage distance levels specified by national standards are:
Class II Medium pollution area: specific creepage distance 20mm/kV
Class III Heavy pollution area: specific creepage distance 25mm/kV
Class IV Very heavy pollution area: specific creepage distance 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 zinc oxide varistors;
(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 the position adjustment is completed, 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 the position adjustment is completed, 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°~5°. Since it is difficult to accurately calculate the interference amount, hard compensation is generally not recommended, and it is set to 0.0°. According to regulations, the trend of data changes over a period of time can be compared longitudinally. If it is necessary to adjust the edge phase correction angle, refer to the relevant sections 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 the "OK" key.
l Mode: Press "OK" to switch among wired, inductive, 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 cyclically display the information of the three phases.
Print: The measured data can be printed out, but not stored.
Store: Store the current data, select the storage location for the data, and press "OK" to save.
Exit: Exit the measurement and return to the system main menu.
7. Data upload: Install the bundled data communication packaging software on the computer, and use a serial communication cable 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, and click the desired function on the computer to complete the relevant operations.
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 the protection effect. The difference between this arrester and traditional arresters is that it has no discharge gap, and the nonlinear characteristics of zinc oxide are used to perform the functions of current release and interruption.
