Lightning protection measures for power transmission lines
Release time: 2025-02-18
With the development of the economy and the continuous growth of electricity demand, the safety issues of power production have become increasingly prominent. For power transmission lines, lightning tripping has always been an important factor affecting the reliability of power supply of high-voltage power transmission lines. Due to the randomness and complexity of atmospheric lightning activities, there are still many unknowns in the world's understanding and research on lightning damage to power transmission lines. In the region, a complex and large high and low voltage distribution network consisting of many power equipment has been built. There are distribution equipment and power-consuming equipment in the distribution network, which are important equipment that affect the quality of electric energy. So far, the lightning protection measures for distribution lines have mainly focused on: (1) How wide is the impact range of lightning overvoltage on a certain high-voltage distribution line and its possible probability; (2) Determine the degree of its lightning protection; (3) Formulate various lightning protection measures that can be used on actual distribution lines. Spark discharge caused by lightning overvoltage is not the cause of burning low-voltage distribution equipment. The spark discharge causes short circuit between the terminals of the distribution equipment. Under the commercial power frequency voltage, short-circuit current (arc discharge) flows between the terminals. The large amount of electric energy at this time is the main reason for burning low-voltage distribution equipment. The frequency of lightning overvoltage in low-voltage distribution lines. The situation of lightning overvoltage in low-voltage distribution lines. From the research on lightning protection measures on distribution lines, the factors that have been considered for lightning overvoltage in low-voltage distribution lines are: 1 Direct lightning (direct lightning strikes on low-voltage distribution lines); 2 Inductive lightning (when lightning strikes the area near the low-voltage distribution line, the induced lightning generated by the distribution line); 3 The lightning overvoltage on the high-voltage side is the cause of the lightning overvoltage invading the low-voltage side. Due to the action of the lightning arrester, the earth (grounding) potential rises, and the lightning overvoltage transitions from the high-voltage side of the pole transformer to the low-voltage side. In fact, in addition to the occurrence of lightning overvoltage on low-voltage distribution lines, there are also situations where lightning current directly penetrates into the lightning rods installed on the buildings near the distribution lines, causing the ground potential to rise and affect the grounding system of the distribution equipment. These should be considered as the synthetic causes of lightning overvoltage. The lightning overvoltage transitions from the high-voltage side to the low-voltage side, and the various situations of lightning overvoltage on the low-voltage distribution line are generally studied. The lightning overvoltage on the high-voltage distribution line invades the low-voltage distribution line and causes the lightning overvoltage to occur. The discharge of the distribution arrester causes the ground potential to rise, and the transition voltage of the pole transformer causes the lightning overvoltage on the low-voltage distribution line. In these studies, lightning pulse voltage should be applied to the actual scale of the high-voltage distribution line. Due to the intrusion of lightning overvoltage into the low-voltage distribution line, at the grounding point (middle grounding) of the overhead common ground wire with the neutral line of the low-voltage distribution line, the line voltage between the lighting line or power line (voltage phase) and the overhead common ground wire (ground phase) is large. Induced lightning overvoltage, measure the voltage waveform induced on the conductor of the distribution line. The effect of suppressing the lightning overvoltage of the overhead ground wire and the shared overhead ground wire of the low-voltage distribution line is significant when the grounding resistance value is small. Because the lightning arrester of the high-voltage distribution line has a moderate action, the high-voltage distribution line is in a grounded state, and it also has the effect of suppressing the lightning overvoltage of the overhead ground wire of the low-voltage line. Install line lightning arresters. Use high-voltage transmission line lightning arresters. Because the installation of lightning arresters makes the potential difference between the tower and the conductor exceed the action voltage of the lightning arrester, the lightning arrester adds shunt to ensure that the insulator does not flash over. We choose to install lightning arresters on high-voltage transmission lines where lightning strikes trip more frequently.
