DC grounding and AC series DC simulation device

Abstract

The invention provides a direct-current earthing and alternating current-directing current series simulation device which is convenient to use and test and capable of overcoming shortcomings in the prior art and performing simulation detection conveniently, visually and quickly. The direct-current earthing and alternating current-directing current series simulation device comprises an operation portion and a control portion which are connected with a power supply, wherein the control portion comprises a keyboard and a display device which are connected with a CPU, and the operation portion comprises an insulation resistor, a bridge resistor, a ground capacitor and a cable capacitor which are connected in sequence and connected onto a wiring terminal group through change-over switches. The direct-current earthing and alternating current-directing current series simulation device has obvious advantages by especially adopting the wiring terminal group capable of performing connection conveniently. By means of the wiring terminal group, connection of the devices is facilitated, and loss caused by misoperation is reduced.

Description

technical field [0001] The present invention relates to a grounding type simulation device of a DC system, and more particularly, the present invention relates to a DC grounding and AC string DC simulation device. Background technique [0002] With the development of the power grid, the calibration of DC grounding devices has developed very rapidly, such as figure 1 As shown, it is the most common DC grounding verification device in the prior art, that is, in the DC load feeder, simulate grounding through resistance, and observe whether the measured value of the grounding resistance by the DC grounding detection device is accurate, whether it can give an alarm correctly, and whether it can Select the ground branch. [0003] This method has a certain inspection effect, and can basically judge whether the grounding detection equipment is working normally. But there are also the following disadvantages: [0004] 1. When simulating a ground fault, it may cause the relay prote...

AI Technical Summary

Problems solved by technology

[0004] 1. When simulating a ground fault, it may cause relay protection to malfunction or refuse to operate, endangering the safe and stable operation of primary equipment or systems

[0005] 2. It can only simulate the single-pole grounding fault of resistance, and the function test of the equipment is incomplete;

[0006] 3. The distributed capacitance parameters of the DC system cannot be simulated, so the performance of the equipment cannot be tested

[0007] In the running DC system, the simulated ground fault may cause the relay protection to malfunction or refuse to operate, making it impossible for the operation and maintenance personnel to simulate other ground faults to check the status of the ground detection equipment, resulting in the failure of the ground detection equipment when the actual ground fault occurs. The actual situation that does not work

According to our survey results on the field use of insulation detection devices, less than 30% of the equipment can correctly alarm and select lines. As a result, in actual operation, when there is a ground fault, the alarm and line selection cannot be performed, and some of them have no ground fault. False alarm, wrong line selection

However, no matter whether it is an inspection device or a portable device, there is currently no unified inspection standard or detection method in China, and the relevant departments cannot regularly inspect the above equipment

At the same time, due to the lack of uniform product quality standards, each manufacturer has its own way, and corporate standards are mixed.

In addition, when manufacturers produce DC grounding detection equipment, they do not systematically conduct functional and safety testing, and the technical indicators are very irregular. When users choose products, they only rely on the propaganda of various manufacturers, and there are no technical indicators for reference and comparison. , so it is difficult to choose a product that meets the actual situation

[0009] Due to the above reasons, in the actual application of these products, it is not known whether the grounding alarm resistance value is accurate, and the grounding line selection is often incorrect. However, the portable grounding search device can sometimes find it and sometimes cannot find it, which makes the operation and maintenance personnel very worried. I am not willing to deal with the grounding fault of the DC system, and have a strong skeptical attitude towards such equipment, which in turn hinders the promotion and application of the equipment, and returns to manual switching to find the grounding method

Because it is very difficult to manually find the grounding, sometimes it will cause safety responsibilities. Some maintenance departments even take chances to reduce the number of grounding alarms by reducing the threshold value of the grounding alarm resistance, which brings hidden dangers to system security.

Images