Portable lightning current generating device and method for grounding device impact impedance testing

Abstract

The invention discloses a portable lightning current generating device and method for grounding device impact impedance testing. The device comprises a power generator and a lightning current generator main loop test box. A rectifying silicon stack D, a charging resistor R1 and a direct-current voltage divider are connected in series to the output end of a boosting transformer T2. An energy-storage capacitor C is connected in parallel to the direct-current voltage divider. One end of a discharging switch S is connected with a positive electrode of the energy-storage capacitor C. The other end of the discharging switch S is connected with an adjustable wave modulated resistor R2. The other end of the adjustable wave modulated resistor R2 is connected with one end of an adjustable wave modulated inductor L. The other end of the adjustable wave modulated inductor L is connected with a grounding grid to be tested through a grounding testing current injection point. A grounding testing reverse current electrode and a reference voltage electrode are arranged on the periphery of the grounding grid to be tested. The ground testing reverse current electrode is connected to a negative electrode of the energy-storage capacitor C of a lightning current generator main loop. The device can simulate inductive effect and soil spark discharging effect really, and impact grounding resistance can be tested really.

Description

【Technical field】 [0001] The invention belongs to the technical field of electric power system grounding, and in particular relates to a portable lightning current generating device and method for testing the impact impedance of a grounding device. 【Background technique】 [0002] The power system has various forms of grounding requirements such as work, lightning protection, and safety. They are an indispensable and important part to ensure the safe and stable operation of the power system. With the realization of the national networking strategy of west-to-east power transmission and north-south mutual supply, my country's electric power industry will maintain rapid growth in the next 15 to 20 years, and a large number of 330kV, 500kV, 750kV and 1000kV super (extra) high voltage substations and towers will need to be built At the same time, in order to ensure the safety of staff and electrical equipment during the operation of the power grid, it is necessary to build a large...

AI Technical Summary

Problems solved by technology

In the current research work at home and abroad, many scholars often design and calculate lightning protection based on the experience of power frequency grounding. However, compared with power frequency current, lightning current has its unique properties. The most important ones are The following two points: First, the frequency of the lightning current is very high, which makes the impact of the inductance effect of the grounding system under the impact current much greater than that under the power frequency. Therefore, the inductance of the grounding system under the impact current The effect must be considered, while the inductive effect of the grounding system is often ignored under the power frequency current

Second, the magnitude of the lightning current is quite high. When the lightning current spreads in the ground, the field strength of the current field is high enough to ionize the soil around the grounding electrode, resulting in a spark discharge effect, thereby changing the surrounding soil. If the electrical characteristics are not considered, it will be seriously out of reality. However, under power frequency, it is difficult to generate such a high electric field strength

However, there are obvious differences between the impact characteristics and power frequency characteristics of the tower. The impact grounding resistance of the grounding device under the action of lightning current and the grounding resistance under the action of power frequency current have different values. The frequency grounding resistance is small, but the tower still suffers from counterattack

The existing technology uses a specific value of concentrated parameter resistance to simulate the grounding device for lightning protection analysis of transmission lines, which cannot truly simulate the effect of inductance and soil spark discharge, and the error is extremely large

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