49results about How to "Does not affect normal power supply" patented technology

The invention discloses a demarcation switching zero-sequence current protection setting value calculation method, and the method comprises the following steps: respectively measuring a capacitive current of a power supply system, then calculating a constant current of a demarcation switch of the power supply system, and then judging that Idz value is greater than the capacitive current of a circuit of the demarcation switch; setting the direction of the capacitive current to point to a grounding point when a grounding fault happens to the system, judging that a zero-sequence current passing through a fault demarcation switch is the capacitive current of the system, and is not related with the capacitive current of the circuit, wherein a zero-sequence current passing through a non-fault circuit demarcation switch is the capacitive current of the circuit, and is not related with the capacitive current of the system. The method is advantageous in that the method prevents air humidity from affecting constant value calculation; the method prevents the unclear quality of a circuit load (the length of a cable circuit is not precise because the cable circuit is buried underground) from affecting the constant value calculation; and the method can prevent a constant value from being modified when the circuit is changed in a small scale, and reduces the workload.

The invention relates to an electricity leakage-prevention and overcurrent protection device. The device comprises a power source input unit A, an output control execution unit Z, an electricity leakage detection unit K and an overcurrent detection unit M which are respectively connected in series with the electricity leakage detection units C1-Cn, the overcurrent detection units D1-Dn and the output control execution units H1-Hn of each branch circuit, wherein the electricity leakage detection units C1-Cn, the overcurrent detection units D1-Dn and the output control execution units H1-Hn of each branch circuit are connected in parallel; a DC power source unit E is respectively connected with an earth detection unit B and a microcontrol unit F; and the microcontrol unit F is respectively connected with the earth detection unit B, the electricity leakage detection units C1-Cn, the overcurrent detection units D1-Dn, the output control execution units H1-Hn, the output control execution unit Z, the electricity leakage detection unit K and the overcurrent detection unit M.

Disclosed is a sliding-type switching device used for main-connection-line short circuit precheck of a low-voltage circuit breaker and the switching device belongs to the field of accessories of low-voltage electric appliances. The low-voltage circuit breaker includes contact systems, a center shaft, a locking device, an operating handle, a base and an arc extinction chamber. The contact systems include dynamic contact mechanisms. The dynamic contact mechanisms include dynamic-contact contact arms. Each sliding-type switching device is characterized by including a precheck contact plate, a pair of sliding contact shoes and a pair of sliding contact plates. Each precheck contact plate is installed at the middle part of one side of a corresponding dynamic-contact contact arm, backing on to a corresponding static contact mechanism. The pair of sliding contact shoes are fixed at the two ends of a corresponding precheck contact plate. Each pair of sliding contact plates are fixed on the base and are in slide cooperation with a corresponding pair of sliding contact shoes. Each sliding contact plate includes a fixing plate. Each fixing plate is provided with insulating layers near the two ends of the upper surface along a slide rail of a corresponding contact shoe and a conductive layer at the middle part. When the sliding contact shoes slide to the conductive layers, the sliding contact shoes are electrically connected with the conductive layers. The sliding-type switching device can be used for detecting short-circuit faults of a load-side main connection line before switch-on of a low-voltage circuit breaker.

The invention provides a miniature circuit breaker level relative inserting wire inletting structure which comprises a miniature circuit breaker and busbars. Half of the one end of the miniature circuit breaker is provided with a plurality of rectangular teeth which correspond to the busbars, a plug-in busbar conductive clamping head of the wire inletting end of the miniature circuit breaker is arranged in a groove which is formed between a certain pair of rectangular teeth; one ends of the pairs of rectangular teeth of the miniature circuit breaker are connected at the two sides of the busbars in a relative and inserted mode, each plug-in busbar conductive clamping head of the miniature circuit breaker is connected to one busbar in a clamped mode, and the rectangular teeth at the half of a miniature circuit breaker is matched with the rectangular teeth at the half of another miniature circuit breaker in relatively inserted mode. Terminal distribution boxes produced through the connection mode of the circuit breaker can be precast and produced according to the standard series, and a box body, a guide rail, a wire inletting busbar and a zero busbar can be preset and integrated. Users only needs to design the loop number and switch capacity according to demands of the users and insert the switches into the system in sequence, and the final assembly is completed, dismantling and maintenance are greatly facilitated, and standard, high efficiency and low cost can be achieved.

The invention discloses a method and a system for online monitoring of dielectric loss and capacitance of a capacitor voltage transformer. According to the method, a voltage / current monitoring device is used for obtaining secondary voltage of a busbar PT, secondary voltage of the capacitor voltage transformer, piezoelectric capacitance current in the capacitor voltage transformer and primary current of an intermediate transformer of the voltage transformer and sending the obtained data to a data processing device for calculation. The method and the system have the advantages that automatic online monitoring of the dielectric loss and the capacitance of the capacitor voltage transformer is achieved, definite physical significance and accurate measurement results are obtained, and fault positions of the capacitor voltage transformer can be judged and positioned accurately; assembly and disassembly of a high-voltage primary lead wire of the capacitor voltage transformer are avoided, onsite measurement workload is reduced, and all test operations can be conducted without powering off, so that normal power supply of an electrical power system is unaffected.

The invention relates to an insulation protection arc-extinguishing drop-out fuse switch which comprises a drop-out fuse switch body (1) and a fuse tube (2). The upper end of the insulator (11) of the drop-out fuse switch body (1) is provided with a power-supply-side static contact insulation protection rack (14), and the lower end is provided with a load-side static contact insulation protection rack (19). The upper end of the insulation tube (21) of the fuse tube (2) is provided with a power-supply-side moving contact insulation protection rack (25), and the lower end is provided with a load-side moving contact insulation protection rack (26). The fixed insulator (27) of the load-side moving contact insulation protection rack (26) is fixedly mounted at the lower end of the insulation tube (21). A movable insulator (28) is hinged with the fixed insulator (27). The insulation protection arc-extinguishing drop-out fuse switch has advantages of high insulation protection performance, effective prevention for grounding and interphase shortcircuit or human electric shock accident, automatic fuse tube falling in fusing break of the fuse, effective prevention for fuse tube damage caused by continuous electric arc generation in the fuse tube, no electric charge of the fuse tube in detachment of the fuse tube, and low danger in operation.