Questions about the leakage current test of the arrester

Huatian Power HTTYB-3H Zinc Oxide Arrester Characteristics Tester.

1.AC test can be used, and the conversion unit is the root 2 relationship, which is called power frequency current test, and the effect is the same.

2.1-10mA is fine.

The voltage is 1 mA

1. You can also use AC, you can try it to know why you don't use AC, because the DC voltage requires less power and less damage to the equipment;

MA, it can basically be regarded as a lightning arrester discharge;

3. The arrester is a nonlinear element, and the current under the voltage of 75 1mA should be very small. If there is a problem with the arrester, the current under 75 1mA is relatively large, and then the arrester should be replaced.

These data are to be recorded, compared year by year, and found that there is a big difference with the data of previous years, that is, the equipment is aging!

Big brother, you won't ask the master directly 1 DC can highlight the problem of the equipment more than AC during the electrical test and will not damage the equipment It will also reduce the possibility of harm to the human body 2 How much voltage will appear in the unit current This is easy to calculate This is the master is lazy 3 I saw it in a book... But forgot ... Alas.

The operator of a 220kV substation found the 4563 lightning arrester of the Yunxia line during the equipment inspection.

B-phase leakage ammeter.

The displayed value is large (A, B, and C, respectively.) 5ma）。The testers went to the site to inspect and found that the glass surface of the B phase leakage ammeter was worn and the readings were blurred.

However, after the new leakage ammeter readings stabilized, the data was the same as before the leakage ammeter was replaced.

2 Infrared temperature measurement of lightning arrester The results of infrared temperature measurement of this group of arresters show that the temperature difference between the middle flange of phase B arrester (divided into upper and lower sections) near the bottom porcelain sleeve of the upper section and the other two phases reaches 3 (phase A is 2131, phase b is 2498, C phase is 21

44℃）。The infrared thermal imaging characteristics of the arrester are: the overall slight heating under normal conditions.

The hot spots are generally close to the upper part and uneven, and the temperature of each section decreases from top to bottom in the multi-node combination. Global fever or localized fever is abnormal. According to Appendix B1. The criterion and thermal image characteristics preliminarily judge that the valve plate of the phase arrester is aged or damp, and the defect level is critical.

3. Arrester power failure test: The arrester is tested after the power is off. The arrester model is Y10W-204 532W, and the continuous operating voltage is 159kV. In order to facilitate data comparison, the upper section of phase A was also tested.

The trial data are shown in Table 1. As can be seen from Table 1, the DC and AC parameters of the upper section arrester of phase B deviate greatly from the normal values. Checking the historical test data of the arrester, the three-phase data of the handover test is normal, the latest power failure test data is also normal, and the latest live test data is balanced and normal.

In order to find out the cause of the arrester failure, it was decided to dismantle it.

4. Disintegration of the arrester Dismantle the upper part of phase B and open the explosion-proof membrane.

It was found that the inside of the explosion-proof film was dry and there was no dirt and no signs of moisture, and the source was sealed several times.

Intact and no anomalies found. Open the explosion-proof membrane at the bottom of the arrester, and find that the bottom seal ring is deformed and damaged (as shown in Figure 2), and the seal ring damage may be caused by negligent assembly slag cracking. Although the inside of the explosion-proof film is not wet, there is a dirt formed by moisture and powder together.

The indicator is set to be no more than 50 A at the bottom of the leakage, and in principle, the smaller the better, taking into account the range of voltage fluctuations. The leakage current can reflect the imitation insulation of the bent car of the arrester, which is an important means to judge the quality of the arrester under the operating voltage.

The current passing through the zinc oxide buried fiber resistor is called the leakage current of the zinc oxide arrester sail hail, which is also considered to be the total leakage current of the arrester. Under the normal rated power frequency voltage, the arrester can be regarded as an insulator.

Leakage current refers to the current flowing through the core of the valve plate of the arrester after the arrester is connected to the system. Because arresters are usually similar to insulators, this current is quite small in the absence of overvoltage. Approximately no more than 1ma.

If it becomes larger, it means that the performance of the valve in the core of the arrester has decreased, **The monitor has an ammeter, which has a green, yellow and red range, the pointer is in the green range, the performance is good, the yellow range means that the leakage current is slightly larger, and the red range indicates that the arrester needs to be replaced. Because the arrester is a fully enclosed integral equipment, there is generally no maintenance statement.

The leakage current (total current) of a complete MOA can be divided into three parts: the capacitive current generated by the zinc oxide valve plate (column), the nonlinear resistive current generated by the zinc oxide valve plate (column), and the current generated by the arrester insulation structure.

If the leakage current generated by the insulating structure increases, the peak value of the total current will also increase. On rainy days, pollution is severe, and the current is generally high. Of course, there is also a low current due to the structure.

In addition to this increase in leakage current, caused by the internal valve plate of the arrester, the arrester needs to be tested and "decommissioned". **The green zone, the yellow zone, and the red zone on the monitoring have a certain warning effect, but in the use experience, the performance is not good in the green zone, and the red zone surface fiber shows that the arrester needs to be replaced.

Introduction: Arresters are crucial in ensuring the proper operation of electrical equipment, but when the leakage current of arresters exceeds the standard, breakdown damage may occur. What is the leakage current of the arrester, and what are the reasons for the excessive leakage current of the arrester, this article will interpret it for you, and I hope to help my colleagues.

For professional power grid technicians, it can be said that it is a relatively common situation to encounter excessive leakage current of lightning arrester in their work. So what is lightning arrester leakage current? Arrester guess which hail leakage current exceeds the standard, what are the reasons for the exceedance, the following Tuba Rabbit will take you to learn together.

What is lightning arrester leakage current

Professionally speaking, the leakage current of the arrester refers to the current flowing through the arrester when it is working under the normal rated voltage. Generally speaking, the arrester can be regarded as an insulator under normal working conditions, and when there is no overcurrent voltage, the leakage current value of the arrester is very small, generally not exceeding 1mA. However, with the long-term work of the arrester, coupled with the influence of external factors, the performance of the valve inside the arrester will decrease, and the leakage current value of the arrester will become larger.

The leakage current of the arrester reflects the degree of insulation of the arrester to a certain extent, and it is also an extremely important aspect to judge the performance of the arrester under the voltage operating state.

What are the reasons for the excessive leakage current of the lightning arrester?

1. Temperature. The magnitude of temperature is one of the important factors affecting the leakage current of the arrester. When the temperature rises, the leakage current of the arrester increases.

When the temperature rises, the arrester can not dissipate heat in time, and the temperature of the resistor will increase, which will cause the resistive current of the arrester to increase.

2. Filth. Contamination on the outside of the arrester can affect the voltage distribution of the resistor column, resulting in an increase in the leakage current of the arrester.

High-voltage connection wires. As we all know, the arrester is installed on the high-voltage wire, when the field strength on the surface of the high-voltage wire is too high, the air of the high-voltage wire will be ionized, which further affects the leakage current of the arrester.

3. Humidity. The higher the humidity of the air, the higher the leakage current of the arrester, especially in rain and snow.

The harmonic content in the voltage at both ends of the arrester. The harmonic content in the voltage at both ends of the arrester can have an impact on the measured value of the leakage current of the arrester, especially when using leakage current measuring instruments manufactured according to the principle of harmonic method.

4. Uniform pressure ring spike sail. If the arrester is not installed with a equalizing ring, and the technician directly measures the leakage current of the arrester, the leakage current value of the arrester will generally be large.

There are many reasons for the excessive leakage current of the arrester, and the professional and technical personnel should diagnose it from both external and internal aspects, so as to determine the cause of the excessive leakage current of the arrester.

You can get it for free

The leakage standard of the arrester is changed to mean that the air standard is not more than 50 microamperes under milliamperes.

The current passing through the zinc oxide resistor is called the leakage current of the zinc oxide arrester, which is also considered to be the total leakage current of the arrester.

Under the normal rated power frequency voltage, the lightning arrester can be regarded as an insulator, so considering the voltage fluctuation range, the index is set to leak no more than 50 microamperes under milliampere, in principle, the smaller the better.

The leakage current can reflect the insulation of the arrester, which is an important means to judge the quality of the arrester under the operating voltage.