【正文】 stem counter the disruption caused damage and, therefore, the second weak system substation and a minevoltage must also take the appropriate protective measures, in accordance with the IEC within the mine area EMP, the device39。s power cord, signal Lines, data lines, and the installation of lightning protection and internal overvoltage devices to prevent lightning sensors, channeling people along the lightning current, voltage counterattack, such as transient voltage surge too transient overvoltage caused by a fault and damaged electronic equipment. Overvoltage surge protection in accordance with its connection mode is divided into two series and parallel, the use of overvoltage surge protection tandem with, there may exist because of signal transmission does not match the causes of transmission of the signal interference, in particular data Communication Interface in the series were overvoltage surge protection in place, will have the normal data munications. Therefore, the data munications access I: I in the series were overvoltage surge protection in place, the transmission of data must be carried out conscientiously check if the data are not normal transmission, it may be due to the reasons do not match the transmission signal Interference, should be replaced to match the overvoltage surge protection for. If the use of overvoltage surge protection for use of parallel, the situation is basically nonexistent, but the connection mode of overvoltage surge protection for higher technical requirements. 3 secondary system overvoltage substation protection points overvoltage electricity system protection Substation installed in the munications dispatch automation systems are used AC power or a DC power supply equipment for the rectification of its links are generally larger capacity filter capacitance, the transient overvoltage shock absorption of a certain extent, the station Lowvoltage transformer side go to feed between the screen using a shielded cable and equipment have a good grounding, the use of modern technology to analyze mine, we must increase the circuit39。s ability to bear a very low voltage, several hundred volts of overvoltage is enough to damage the equipment, so must the high side arrester the residual pressure (thousands of volts) to further curb to meet equipment Insulation level of need, and because of the potential rise to power and the induction loop is also overvoltage line up on KV, to be used in the exchange of integrated automation system to the exchange on the clevel singlephase installation of a surge Voltage protection. Location should choose to install automatedping in the Composite Air switch the AC power. did not ask off power supplies (UPS) overvoltage protection Protection here: because of the internal puter systems, hubs, monitoring equipment, electric energy billing systems and so on through the UPS power supply protection, in order to protect the safety of these microelectronics equipment, the UPS power supply device in front of the installation of a cSurge Voltage protection. Optional models: The (UPS for singlephase power input) Cclass singlephase power surge or overvoltage protection (UPS for the threephase power input) of clevel threephase power supply overvoltage surge protector. Installation should choose the location of UPS into the front line. munication interface overvoltage protection Communication Interface overvoltage protection pared with the grid supply system, this overvoltage circuit on the degree of sensitivity is much higher, and these are overvoltage equipment in the circumstances it is very fragile. Equipment insulation tolerance level is very low. With the equipment connected to a signal line, data lines, measurement and control lines, and these are basically in line LPZOB region, but also through the LVZOA region, on the lines of sensors overvoltage relatively strong, according to the IEC test, when the electromagic field Strength increased to GS, will have a microputer equipment malfunction, loss of data. And the safety of these circuits is directly r