5 results about "Overcurrent relay" patented technology

The invention relates to the technical field of locomotive line detection, in particular to a line detection system and device for a locomotive main transformer, and the system comprises a transformer which comprises an input side and an output side, the input side is used for being connected with a power supply, the output side comprises an end a and an end n, the end a is used for being connected with the end A of the main transformer, and the end n is used for being connected with the end X of the main transformer; the end a is connected with an over-current relay; the input side is connected with a conduction test loop, an operation test loop and an overload test loop; the conduction test loop is used for testing the conduction states of the main transformer, the a end and the n end; the operation test loop is used for carrying out power supply detection on the main transformer; when the transformer is in overload operation, the overcurrent relay drives the overload test loop to be conducted; therefore, through the arrangement of the conduction test loop, the operation test loop and the overload test loop, the conduction state, the power supply condition and the overload condition of the main transformer line can be rapidly detected, and cumbersome connection and disconnection operation is not needed.

The utility model discloses a control loop of an external motor cooling device, which relates to the technical field of cooling device control, and is characterized in that a main motor, a current transformer and a current relay are arranged, so that a power line of the main motor is connected with the current transformer, and the current transformer is in mutual inductance connection with the current relay; the current relay is connected in series with the cooling device, and when the current passing through the current relay reaches a set value, the auxiliary contact of the current relay is automatically closed, and the cooling device is automatically started at the same time, so that heat dissipation and temperature reduction are carried out on the main motor; the cooling device can achieve the automatic start-stop function according to the change of the load, it is ensured that the cooling device can be rapidly and effectively put into use under the large-load condition, an operator does not need to conduct on-site operation, and therefore great convenience is brought to the operator.

The application discloses a welding power supply device with short-circuit protection function, which comprises a welding box, a power supply unit, a voltage and current display, a transformer, a fuse, an overcurrent relay and a thermistor unit, the power supply unit is installed on the inner upper side of the welding box, a control panel is arranged in the welding box, the voltage and current display is connected with the control panel, a main circuit is connected outside the transformer, the fuse is arranged in the main circuit, a connecting port is arranged outside the welding box, the main circuit is connected with the connecting port through internal wiring, and the overcurrent relay is arranged in series on the main circuit; the thermistor unit is installed in parallel with the overcurrent relay on the same section of the main circuit; the welding power supply device can realize double short-circuit protection, the thermistor unit arranged in parallel on the main circuit can freely adjust the series or parallel monitoring of the variable resistance unit with different resistance values, effectively cope with the problems of instantaneous large current and overheating, and reduce the possibility of false triggering.

The utility model relates to the technical field of power distribution cabinets, in particular to a power distribution cabinet capable of preventing an overcurrent fault, which comprises an overcurrent fault prevention mechanism comprising a power distribution box. According to the utility model, the interior of the power distribution cabinet is designed into a multi-layer structure through the drawing mechanism, different types of elements are placed on the bottom layer, the middle layer and the upper layer respectively, the vertical space is reasonably utilized, the problem of unreasonable internal space layout of a traditional power distribution cabinet is solved, different types of elements are installed in a layered and isolated manner, electromagnetic interference is reduced, and electrical isolation is ensured; the arrangement of the hollowed-out partition plates not only ensures the electrical isolation among the layers, but also provides a channel for ventilation and heat dissipation, effectively avoids the thermal interference of high-temperature elements on key components such as an overcurrent prevention relay and the like, improves the accuracy of overcurrent fault detection and processing, and can directly pull out the drawing mechanism during maintenance, thereby avoiding the operation in a compact space, and reducing the maintenance cost. The operation difficulty and the risk of new faults caused by misoperation are reduced, and the convenience and safety of maintenance are improved.

The application discloses a fault processing technology for a "double-high" type novel power distribution network. The method first constructs a fault database covering multiple scenes based on short-circuit calculation and a fault sample generation mechanism; then, voltage / current time series are normalized and polar coordinate mapping is performed, and Gramian Angular Summation Field (GASF) is used to convert the time series into a two-dimensional image; further, a convolutional neural network is used to extract multi-channel image features and output fault categories; finally, according to the fault categories and short-circuit current levels, the pickup current and time scale coefficient of the directional overcurrent relay are updated online, and a nonlinear optimization model is established under the condition of constraining the coordination time interval of the main and standby relays to solve the optimal relay setting value of the minimum total action time. Compared with the traditional fixed setting value scheme, the application can significantly improve the fault classification accuracy and protection action speed of the power distribution network and realize adaptive protection coordination under a complex source-network-load-storage scene.