Lightning protection measures for Substation

Lightning protection measures for substation

substation is an important part of power system. Lightning stroke accident in substation will cause large-area power failure and cause great harm to electricity, which requires that lightning protection measures must be very reliable

the lightning strike suffered by the substation mainly comes from two aspects: first, the lightning strike directly on the electrical equipment of the substation; Second, the lightning wave formed by induced lightning overvoltage and direct lightning overvoltage of overhead lines invades the substation along the line. Therefore, the protection of direct lightning strike and lightning intrusion wave against the damage of substation incoming line and transformer is very important

direct lightning protection of substation. Installation of lightning rod is the main measure for direct lightning protection, and lightning rod is the lightning receiver to protect electrical equipment and buildings from direct lightning strike. It attracts the lightning to itself and leads it safely into the ground, thus protecting the nearby equipment with lower insulation level from lightning strike

when installing lightning rods, the 35 kV substation must be equipped with independent lightning rods and meet the requirements of no counterattack; For substations of 110kV and above, due to the high insulation level of distribution devices with such voltage levels, lightning rods can be directly installed on the structure of distribution devices. Therefore, the high potential generated by lightning rods will not cause electrical equipment counterattack accidents

protection of substation against lightning intrusion wave. The main measure to protect the inrush wave in the substation is to install a valve type lightning arrester or a protective gap on its incoming line. The basic components of valve type arresters are spark gap and nonlinear resistance. At present, FS series valve type arresters are spark gap and nonlinear resistance, which are mainly used to protect the small capacity distribution device sFz series valve type arresters, which are mainly used to protect the electrical equipment of medium and large capacity substations; Fcz1 series magnetic blow valve arresters are mainly used to protect high-voltage electrical equipment in substations

incoming line protection of substation. The purpose of lightning protection for the incoming line of substation is to limit the amplitude of lightning current flowing through the arrester and the steepness of lightning wave. When overvoltage occurs on the line, there will be traveling waves traveling along the conductor to the substation, with the amplitude of 50% of the impulse flashover voltage of the line insulation. The impulse withstand voltage of the line is much higher than that of the substation equipment. Therefore, installing lightning conductor on the incoming line near the substation is the main measure for lightning protection. If the lightning conductor is not erected, when the incoming line close to the substation is struck by lightning and wins the Platts Global Energy annual breakthrough solution award that year, the amplitude of lightning current flowing through the arrester can exceed 5ka, and its steepness will also exceed the allowable value, which is bound to cause damage to the line

transformer protection. The basic protection measure for the transformer is to install lightning arrester near the transformer, so as to prevent the insulation from being damaged by the lightning wave invaded by the line

when installing the lightning arrester, it shall be as close to the transformer as possible, and the length of the connecting line shall be reduced as far as possible, so as to reduce the voltage drop of the lightning current on the connecting line through the slip of the measured data. At the same time, the wiring of the arrester shall be connected with the metal shell of the transformer and the neutral point at the low-voltage side. In this way, when the surge wave makes the arrester act, the voltage acting on the main insulation at the high-voltage side will only be the residual voltage of the arrester (excluding the voltage drop on the grounding resistance), which reduces the chance of lightning damage to the transformer

lightning protection and grounding of substation. The load sensor on the loading actuator ensures the accuracy of the loading force value; The spindle mechanism is driven by the control machine and the ball screw runs along the X axis, and the displacement is controlled by the high-precision displacement measuring mechanism. After the lightning protection of the substation meets the requirements, a unified grounding should be laid according to the requirements of safety and working grounding, and then the grounding body should be added under the lightning rod and arrester to meet the lightning protection requirements, or a separate grounding body should be laid under the lightning protection device