Example embodiments relate to luminaire systems with SPD. One example luminaire system includes a luminaire housing, a support with at least one light source arranged thereon, a drive means configured for driving the at least one light source, a surge protection device between a power supply and the drive means, and an indicator device. The surge protection device includes surge protection circuitry and monitoring circuitry configured to monitor a malfunctioning of the surge protection circuitry and provide an output signal based on the monitoring. The monitoring circuitry is connected such that a state of the indicator device is changed when the output signal indicates a malfunctioning. The indicator device is arranged at a location which is such that the state of the indicator device is visible from outside of the luminaire housing.

A power semiconductor circuit is provided for clamping the voltage across the circuit when a power semiconductor switch is opened (i.e., turned off). The circuit may include a first surge arrester and a first semiconductor switch coupled in parallel with the power semiconductor switch. The first semiconductor switch is coupled in series with the first surge arrester. A second surge arrester may be coupled to the gate of the first semiconductor switch to control current flow through the first semiconductor switch and the first surge arrester.

An electrical fuse assembly includes electrically conductive first and second electrodes, and a bimetallic fuse element. The bimetallic fuse element electrically connects the first and second electrodes. The bimetallic fuse element is configured to disintegrate, and thereby disconnect the first electrode from the second electrode, in response to a current exceeding a prescribed trigger current of the bimetallic fuse element for at least a prescribed duration.

The present invention performs a reference point detecting step (S20) to select a reference point by performing pattern analysis based on a characteristic pattern shown in a total leakage current (I.sub.T) when an applied voltage is 0V, a resistive leakage current calculating step (S30) to calculate a resistive leakage current by Fourier series-expanding the total leakage current (I.sub.T) starting at the reference point, and reference point verifying/correcting steps (S40 and S41) to correct the reference point until a characteristic pattern of the resistive leakage current (I.sub.R) according to non-linear resistance characteristics of the surge arrester (1) is shown so that the resistive leakage current (I.sub.R) is recalculated, and the present invention determines that the resistive leakage current (I.sub.R) calculated based on the completely corrected reference point is the resistive leakage current of the surge arrester (1).

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.

An apparatus includes a plurality of surge protection devices (e.g., multiple metal oxide varistors connected in parallel) configured to be coupled to a power system, a plurality of mechanical actuators associated with respective ones of the surge protection devices and configured to indicate status of the associated surge protection devices, and a detector circuit configured to sense actuation of the actuators and responsively determine a protection status of the plurality of surge protection devices. The detector circuit may include a plurality of switches configured to be actuated by respective ones of the actuators. The detector circuit may further include a processor coupled to the plurality of switches and configured to determine states of switches and to determine the protection status based on the determined status of the switches. The processor may be configured to interpret the status of the switches based on a stored identifier.

An overvoltage protection circuit which can be applied to a motor controller is provided. The overvoltage protection circuit is coupled to an input terminal for receiving an input voltage. The overvoltage protection circuit comprises a switch circuit, a controller, and a comparing unit. When the input voltage is greater than a first voltage, a discharging mechanism is forced to start so as to suppress a voltage spike. When the input voltage is less than a second voltage, the discharging mechanism is closed so as to operate normally.

A lighting relay panel may include lower-cost features or components related to improved safety and reliability. In some cases, the relay panel includes a power supply capable of protecting the panel from high-voltage and high-current transients. A microcontroller may determine a power interruption based on a zero-cross signal received from the power supply, and may also configure latching relays during the interruption. In some implementations, the relay panel includes a relay sense circuit that is capable of receiving actuation signals from multiple relays connected to different phases of a power signal, and the microcontroller may synchronize or repeat the actuations based on a signal from the relay sense circuit. The microcontroller may generate relay addresses based on the relay positions within the relay panel. In some cases, the relay panel may include isolation circuits that are capable of providing an isolated control signal having an improved voltage range.

An electronic device includes an input, an output, a metal fuse, a resistor, a heat control transistor, and a heat controller. The metal fuse is coupled between the input and the output. The resistor is coupled between the metal fuse and the heat control transistor. The heat control transistor is coupled between the resistor and a reference terminal of the electronic device, and the heat controller is configured to control a heater current of the heat control transistor.

A method for reducing and/or managing energy-related stress in an electrical system includes processing electrical measurement data from or derived from energy-related signals captured by at least one intelligent electronic device (IED) in the electrical system to identify and track at least one energy-related transient in the electrical system. An impact of the at least one energy-related transient on equipment in the electrical system is quantified, and one or more transient-related alarms are generated in response to the impact of the at least one energy-related transient being near, within or above a predetermined range of the stress tolerance of the equipment. The transient-related alarms are prioritized based in part on at least one of the stress tolerance of the equipment, the stress associated with one or more transient events, and accumulated energy-related stress on the equipment. One or more actions are taken in the electrical system in response to the transient-related alarms to reduce energy-related stress on the equipment in the electrical system.