63 results about "Power systems protection" patented technology

A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.

A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.

The invention discloses a protection device outlet relay circuit impedance matching calculation method. The method comprises the steps that the input target voltage of an outlet relay circuit is calculated according to the input voltage range of the outlet relay circuit; according to the input target voltage, the action current of a relay and the resistance of a relay coil, the resistance of series resistors of the relay is calculated; the percentage of the resistance of the relay coil to the total resistance of the outlet relay circuit is calculated; and according to the percentage, the action voltage range of the relay is calculated. According to the invention, the reliable action voltage range of the relay is calculated according to the input voltage range of the outlet relay circuit and the percentage of the resistance of the relay coil; the voltage matches the rated resistance of the relay; and the reliability of a power system protection device is improved.

The invention relates to a power transmission line fault continuity judgment method based on image features, and belongs to the technical field of power system protection. Fault traveling wave data at the end of a power transmission line are collected, and a proper data window is selected based on linear calibration; displaying a proper data window in the image, and constructing a triangular bounding box which is well close to the region of interest; calculating the ratio of the continuation area formed by the fault traveling wave and the external tangent line in the bounding box to the whole bounding box, and judging whether a fault initial wave head exists or not according to the ratio; on the basis of existence of a fault initial wave head, regularization of initial and subsequent wave heads is carried out, relative characteristics of an arrival time sequence, a wave head amplitude and a slope are calculated based on the regularized calibration wave head, and finally fault continuity discrimination is realized. According to the method, the fault data without the traveling wave head can be automatically screened out, and the line fault traveling wave accessibility can be judged.

The present invention relates to the technical field of power system protection and fault detection, in particular to a method for modeling and analyzing arc-ground faults in distribution networks, which includes the following steps: Step 1. Establish a grounding variable resistance model of a fault branch, and the grounding can be The grounding variable resistance in the variable resistance model is the grounding resistance of the fault point on the fault branch; Step 2, establishes the short-gap breakdown arc model of the fault branch, and the short-gap breakdown arc model is the fault point on the fault branch The arc arc voltage; step 3, combining the grounding variable resistance model and the short gap breakdown arc model to establish a distribution network arc ground fault model based on the breakdown gap and variable resistance in different scenarios. The invention has the characteristics of obvious zero-break characteristic and accurate response to various types of grounding faults, provides sufficient theoretical support for the research and simulation of grounding faults in the subsequent lifting distribution network, and has strong practicability.

The invention relates to a multifunctional power system protection device, which belongs to the field of power system protection equipment. The device can switch between flat ground and rough roads, the device can change the height, the device can dissipate heat, the device can prevent the system from being polluted by dust, and the device can Clean the filter screen, the device can prevent collision, the device can be easily disassembled, the device can peel the cable, the device can cut the cable, and the device can protect the cutting knife. The multi-functional mobile wheel mechanism is located under the protective shell mechanism. The multi-functional mobile wheel mechanism is used for the movement of the device. The protective shell mechanism is used for heat dissipation and storage of dust pollution. The anti-collision dust cleaning seat mechanism is welded on both sides of the protective shell mechanism. The connection mode between the cable peeling mechanism and the protective shell mechanism is welding, the connection mode between the cable cutting mechanism and the protective shell mechanism is welding, the anti-collision dust cleaning seat mechanism is used for dust removal, the cable peeling mechanism is used for cable peeling, and the cable cutoff Mechanism for cutting cables.