The present invention is applied to a power system of a power plant including a three-winding transformer, and relates to a double incoming breaker system, including: a plurality of main circuit breakers respectively connected one by one to the plurality of first non-safety class high voltage buses and the plurality of second non-safety class high voltage buses; a plurality of auxiliary circuit breakers, one of which is connected in series to one of the plurality of main circuit breakers; a first power source measurer installed to correspond to the main circuit breaker and measuring a power source level of a non-safety class high voltage bus applied to the main circuit breaker; a second power source measurer installed to correspond to the auxiliary circuit breaker and measuring a power source level at an installed first point thereof; and a controller that outputs a first open signal to the main circuit breaker when an abnormal situation of the non-safety class high voltage bus is checked through the power source level measured by the first power source measurer, and outputs a second open signal to the auxiliary circuit breaker when it is determined that the main circuit breaker fails through the power source level at the first point measured by the second power source measurer after outputting the first open signal.

A circuit for a circuit interrupter is provided. The circuit may in include a first SCR configured to receive a first trigger signal at a gate of the first SCR, a second SCR configured to receive a second trigger signal at a gate of the second SCR, and a third SCR configured to receive a third trigger signal at a gate of the third SCR. A cathode of the first SCR may be connected to an anode of the third SCR. A cathode of the second SCR and a cathode of the third SCR may be connected to a ground. Methods of operating a circuit interrupter and a circuit are also provided.

A battery unit includes a positive relay switch, a negative relay switch, a first resistor disposed in a third wiring portion extending between a positive external terminal and a negative external terminal, a second resistor serially connected to a portion on more negative side than the first resistor, a third resistor disposed in a second wiring portion and connected in parallel with the negative relay switch, a potential difference detection section capable of detecting a first potential difference which is a potential difference between the portion of the third wiring portion on more negative side than the first resistor and a negative terminal and a failure determination section for determining a failure of the positive relay switch and the negative relay switch respectively, based on the first potential difference.

A leakage current detection and interruption (LCDI) device for a power cord includes a switch module that controls an electrical connection of first and second power supply lines between input and an output ends; a leakage current detection module, including first and second leakage current detection lines, which respectively cover the first and second power supply lines, and are respectively configured to detect leakage current signals on the first and second power supply lines and to generate self-test fault signals in response to the first and second leakage current detection lines having an open circuit; and a drive module which receives the first and/or second leakage current signal and the first and/or second self-test fault signal, and drives the switch module to disconnect the electrical connection in response to these signals. The LCDI device can individually detect leaks on the two power supply lines and open circuit on the two leakage current detection lines.

The present disclosure a program burning device configured to read or write to a program burning interface. The program burning device includes a microprocessor, a programming drive circuit and an overcurrent protection circuit. The microprocessor outputs a first test signal or a second test signal. The programming drive circuit outputs a high driving voltage or a low driving voltage to the program burning interface. After the programming drive circuit outputs the low driving voltage for a preset time, the programming drive circuit outputs the high driving voltage to make the program burning interface form a high impedance. Afterwards, the overcurrent protection circuit receives the first test signal to trigger the overcurrent protection, and then receives the second test signal to trigger the undercurrent protection. If triggering the overcurrent protection and the undercurrent protection are continuously failed over a preset number of times, the microprocessor determines that current protection is failed.

Systems and methods for testing a lightning protection circuit are provided. Aspects include providing an alternating current (AC) test signal source coupled to a circuit under test, the circuit under test comprising a lightning protection circuit having a threshold voltage, a first filter, and a second filter, providing a direct current (DC) voltage supply in series with a filtering device, the filtering device coupled to the AC test signal source, providing a first capacitor coupled between the AC test signal source and the circuit under test, operating the DC voltage supply and the AC test signal source to provide a first test signal to the circuit under test, wherein the first test signal comprise a first voltage that exceeds the threshold voltage, measuring a first impedance of the circuit under test responsive to providing the first test signal, wherein the first impedance corresponds to the first filter.

A wiring device including an interrupting device and a controller. The interrupting device electrically connects one or more line terminals to one or more load terminals when the interrupting device is in a reset condition and disconnects the line terminals from the load terminals when the interrupting device is in a tripped condition. The controller is configured to, determine a frequency of an input voltage at the one or more line terminals, determine whether the frequency is within a predetermined range, and when the frequency is within the predetermined range, perform a test of the wiring device.

A polarity reversal protection arrangement having a transistor circuit, an amplifier circuit and an output driver stage, wherein the amplifier circuit is connected to the output driver stage and the output driver stage is connected to the transistor circuit and the transistor circuit is arranged between a first connection node and a second connection node of the polarity reversal protection arrangement, such that an electrical connection between the first connection node and the second connection node is able to be created or disconnected by way of the transistor circuit, wherein the output driver stage is designed as a tri-state stage. A method for operating the polarity reversal protection arrangement and to a corresponding use.

A power component includes two electric terminals, a component housing, a main component at least partially surrounded by the component housing, connected with the two terminals, and configured to carry a power current flowing between the two electric terminals, and a sensor and emitter unit which is configured to measure a value of a physical quantity (T, V, ΔV) characterizing an operating state of the main component, and to emit an electromagnetic signal, in which the measured value of the physical quantity is encoded. The sensor and emitter unit includes an antenna for emitting the electromagnetic signal which is spaced apart from the main component and arranged in, on and/or at the component housing.

The aim of the invention is to prevent undesired false triggering of a safety device, which protects a person from electric shock as a result of unintentional contact with voltage-carrying or current-carrying parts. This aim is achieved in that a triggering sensitivity (E.sub.A) of the safety device is changed depending on a determined body resistance (R.sub.K) of the person wearing the safety device.