An over-voltage protection system is provided for use with electrical equipment. The system includes a protection circuit having a first bus for receiving electrical power, a second bus for providing power to the equipment and two parallel surge arresters connected between the first bus and ground. A main and backup bushing are arranged in parallel between the first and second bus. The main bushing is arranged in series with a normally closed contact maintaining the main bushing in service by default. The backup bushing is arranged in series with a normally open contact isolating the backup bushing by default. The protection circuit comprises a controller for testing the insulation of the arresters and bushings. The controller is configured to selectively actuate the contacts to selectively isolate, or incorporate, the arresters and bushings in the circuit to facilitate testing and maintenance while maintaining the protection circuit operational.

A method of remotely monitoring a status of a surge arrester disconnector includes providing a long-range wireless mesh communication system including a plurality of disconnectors organized in a plurality of clusters. Each cluster includes a plurality of disconnectors that are physically located within a same cluster area. At least one of the disconnectors in each cluster is coupled to a communication device of a predetermined communication range. The method includes transmitting, from a first cluster, a status signal indicative of a status of a first disconnector in the first cluster to a second cluster located within the predetermined communication range, and consecutively transmitting the status signal from the second cluster to a third cluster within the predetermined communication range, until reaching an end cluster. The method includes transmitting, from the end cluster, the status signal to a monitoring station, and monitoring the status of the first disconnector at the monitoring station based on a result of transmission of the status signal.

An instrumented electric power voltage arrester includes a temperature sensor, wireless transmitter, and a visual over-temperature indicator. A disk shaped module, a replacement varister block, or a dummy block containing the sensor/transmitter is placed between varister blocks inside the arrester housing. A strap-on module is attached to the outside of the arrester housing. The sensor/transmitter utilizes a harvesting power supply that draws electric power for the electronics from the power line protected by the arrester. An ambient temperature sensor may be utilized to enhance accuracy. The temperature sensor/transmitter typically sends arrester monitoring data wirelessly to an RTU or handheld unit located outside the arrester, which relays the monitoring data to an operations control center that scheduled replacement of the arrester based on the monitoring data. A surge counter keeps track of the number of equipment and lightning related temperature surges experienced by the arrester.

The invention relates to an overvoltage protection device with monitoring and communication functions, in particular for the information and process industries, having at least one surge arrester with a self-diagnostics unit and a wireless and/or wired standard interface for data transmission. According to the invention, an additional module is provided to detect the behaviour and/or the properties of a connected electrical energy source, wherein a bidirectional exchange of data and commands to and between a higher-level control system and among multiple overvoltage protection devices takes place and parametrisation of lower-level terminals to be protected can be realised via the standard interface.

An arrester system has at least two parallel-connected arresters, each with a sensor for determining leakage currents. A monitoring system is configured to detect faults at the arresters by comparing sensor data. The method for detecting faults at parallel-connected arresters includes comparing in particular the present measured values of the arresters and/or from sensors of the arresters. A fault is detected when there are deviations between measured values of different arresters. The arrester system is identified as fault-free when measured values of the arresters, in particular of all arresters, are substantially the same.

An arc detection circuit includes a current detector and arc determination unit. The current detector detects a current flowing through a transmission line which connects an electric power supply device and an electric power conversion circuit. The arc determination unit calculates, from a result of measurement of the current, an area of interest and an area for comparison. The area of interest is an area of a region of interest defined by a predetermined frequency range and predetermined time for determination. The area for comparison is an area of a portion in which detected strength exceeds a predetermined strength threshold in the region of interest. The arc determination unit determines an electric arc has occurred when a ratio between the area of interest and the area for comparison exceeds a predetermined area-ratio threshold.

A method of remotely monitoring a status of a surge arrester disconnector includes providing a long-range wireless mesh communication system including a plurality of disconnectors organized in a plurality of clusters. Each cluster includes a plurality of disconnectors that are physically located within a same cluster area. At least one of the disconnectors in each cluster is coupled to a communication device of a predetermined communication range. The method includes transmitting, from a first cluster, a status signal indicative of a status of a first disconnector in the first cluster to a second cluster located within the predetermined communication range, and consecutively transmitting the status signal from the second cluster to a third cluster within the predetermined communication range, until reaching an end cluster. The method includes transmitting, from the end cluster, the status signal to a monitoring station, and monitoring the status of the first disconnector at the monitoring station based on a result of transmission of the status signal.

A semiconductor integrated circuit of the present disclosure includes: first power and second power supply lines that are coupled to a protected circuit; a third power supply line that is supplied with a voltage different from voltages supplied to the first and second power supply lines; a detection circuit that is coupled between the first and second power supply lines and detects a surge occurring in the first power supply line; an inverter circuit that includes one or more inverters coupled in series, and is coupled between the first and second power supply lines; a protection transistor that is coupled between the first and second power supply lines, and is controlled by an output of the detection circuit to cause the surge to flow through the second power supply line; and a time constant circuit that is coupled to at least the third power supply line and the protection transistor.

A monitoring arrangement for electrical equipment includes a first sensor for sensing a surface creeping current on a creeping path-lengthening electrically insulating housing of the equipment. A monitoring system includes electrical equipment, the monitoring arrangement, a communication device for transmitting data to a central server device, and a central server device configured to receive and evaluate the data.

A sensor to monitor health of surge arresters such as metal oxide arresters is disclosed. The sensor includes a housing; a sensor assembly contained in the housing, the sensor assembly including an electronics board to receive, transmit, process, and store signals; and a voltage measurement strap extending around a periphery of the housing, the voltage measurement strap being electrically connected to the electronics board and configured to measure voltage using electric field.