【Daily Topic】【Electrical Edition 20160810】

1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit.

1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 　　2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 　　3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 　　4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit

Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to the ground, allowing the lightning current to be discharged to the ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. When abnormal voltages or large currents pass through the arrester, it should not overheat or get damaged. When lightning current passes and the voltage returns to normal after a short period, arcing can be quickly extinguished; the resistance becomes extremely high immediately, breaking the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit.

A lightning arrester is a device designed to protect various electrical equipment in power systems from damage caused by lightning overvoltage, switching overvoltage, and power-frequency transient overvoltage. The main types of arresters are protective gaps, valve-type arresters, and zinc oxide arresters. Protection gaps are primarily used to limit atmospheric overvoltages, and are generally employed for the protection of distribution systems, lines, and the incoming sections of substations. Valve-type arresters and zinc oxide arresters are used for the protection of substations and power plants. In systems of 500 KV and below, they are primarily used to limit atmospheric overvoltages; in ultra-high voltage systems, they are also employed to limit internal overvoltages or serve as a backup protection against such overvoltages.

1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 　　2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 　　3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 　　4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit. :lol

1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit.

Low resistance, fast release, and resistant to various harsh weather conditions.

(1) Under normal operating voltage, it has a high insulation resistance relative to ground, equivalent to an open circuit. (2) In the event of abnormal voltages (atmospheric overvoltages), regardless of the level or frequency of these abnormal voltages, the arrester can quickly make a connection to the ground, allowing the lightning current to be discharged to the ground rapidly. (3) When abnormal voltages and currents pass through the arrester, it must not overheat or get damaged. 4) When the normal voltage is restored shortly after the lightning current has passed through, arcing can be quickly extinguished; the resistance becomes extremely high immediately, breaking the connection to ground and stopping the discharge, thereby preventing the normal power-frequency current from flowing through the circuit.

1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 　　2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 　　3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 　　4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit

Answer: 1) Under normal operating voltage, the arrester has a high insulation resistance to ground, equivalent to an open circuit. 2) In the presence of abnormal voltages (such as atmospheric overvoltages), regardless of the frequency of these abnormal voltages, the arrester can quickly make a connection to ground, allowing the lightning current to be discharged to ground rapidly. At this point, the lightning protection resistance becomes very small, approaching a short circuit. 3) When abnormal voltages or large currents pass through the arrester, it must not overheat or get damaged. 4) When the normal voltage is restored after the passage of lightning current or over a short period of time, arcing can be quickly extinguished; the resistance becomes extremely high immediately, cutting off the connection to ground and stopping discharge, thereby preventing the normal power-frequency current from flowing through the circuit.