32results about How to "Reduce step voltage" patented technology

The invention provides a microcomputer arc-extinguishing resonance-elimination overvoltage protection device and relates to the technical field of electric power system arc-extinguishing and resonance-elimination. The microcomputer arc-extinguishing resonance-elimination overvoltage protection device comprises a high-voltage current limiting fuse, a voltage transformer, a three-phase combined overvoltage protector, a vacuum contactor, a microcomputer arc-extinguishing controller, a high-voltage fuse and a zero-sequence current transformer. Three phase ports of the three-phase combined overvoltage protector are respectively connected with a three-phase high-voltage isolation switch. A grounded end is connected with the voltage transformer and then is grounded. The high-voltage fuse is serially connected between three phase ports of the voltage transformer and the three-phase high-voltage isolation switch. A voltage transformer control end of the microcomputer arc-extinguishing controller is connected with the voltage transformer, and a vacuum contactor control end is connected with the vacuum contactor. Three phase ports of the high-voltage current limiting fuse are respectively connected with the three-phase high-voltage isolation switch, and the other end of the high-voltage current limiting fuse is connected with the vacuum contactor. A grounded end of the vacuum contactor is grounded, and a zero-sequence current transformer is arranged between the grounded end and a grounding point. The overvoltage protection device provided by the invention is high is action speed and is capable of realizing arc-extinguishing and resonance-elimination.

The present invention discloses a novel step voltage calculation method based on circular ring-shaped DC power transmission earth electrode different buried depths. The method comprises the followingtwo situations of (1) analyzing the potential distribution that the homogeneous medium circular ring-shaped earth electrodes are not buried at the equal depth to obtain a calculation expression of a step voltage on an earth surface; (2) analyzing the potential distribution that the horizontal dual-layer medium circular ring-shaped earth electrodes are not buried at the equal depth to obtain a calculation expression of the step voltage on the earth surface; utilizing a MALTAB software to simulate to obtain the results and the influence of different earth electrode ring numbers and different buried depths on a surface potential, thereby demonstrating that the method provided by the present invention enables the step voltage to be reduced. The present invention creatively provides the thoughtthat the dual-circular ring-shaped earth electrodes are not buried at the equal depth, the calculation is simple, and the operation speed is fast.

A high-conductivity exothermic solder powder suitable for use in acidic soil, the solder powder includes the following components in parts by weight: copper oxide: 15-20 parts, aluminum powder: 20-25 parts, copper powder: 35 parts -50 parts, alloy powder: 5-15 parts, molybdenum: 3-8 parts, oxygen scavenger: 1-2 parts, slagging agent 1-2 parts, rare earth 1-2 parts, the weight of chromium in the alloy powder The percentage is 25-35%, the weight percentage of manganese is 20-25%, the weight percentage of manganese nitride is 15-25%, and the balance is aluminum. The exothermic solder powder involved in the present invention will not crystallize in acidic soil. Inter-corrosion, good conductivity.

The invention provides a grounding electrode insulation shielding structure used for reducing the pace voltage of grounding electrodes, which comprises the grounding electrode that is arranged under the ground surface, a coke bed covering the grounding electrode, and an insulating barrier that is arranged between the grounding electrode and the ground surface and is used for preventing the electric current from flowing towards superficial layer soil and forcing the electric current from flowing towards submerged soil, thus reducing the pace voltage of the ground surface. According to the structure, the maximum pace voltage is reduced in a way of saving more instruction funds under the condition that the size of the grounding electrode is not increased, and land occupying area is not enlarged.

The invention discloses a lightning-protection manual grounding system and a construction method by utilizing a structure steel bar externally-connected downlead wire. The system comprises a structure steel bar downlead wire (2) fixed into a building structure outer wall column (1) and connected with a lightning arrester on the top of a building. The lightning-protection manual grounding system is characterized in that the downlead wire of the lightning-protection manual grounding system is formed by the structure steel bar downlead wires (2) and a non-structural steel bar downlead wire (5). The structure steel bar downlead wires (2) are connected to form a group through jumper wires. The portions, under the ground, of the structure steel bar downlead wires (2) are transversely and fixedly provided with a connection plate (4); and the connection plate (4) is externally connected to the non-structural steel bar downlead wire (5) which is connected with a manual grounding body (6). The lightning-protection manual grounding system is suitable for the practice that in a reinforced concrete structure, structure steel bars and non-structural steel bars jointly serve as the downlead wires, and the manual grounding body or a composite lightning protection grounding device are used, and limitation of independent foundation, strip foundation, pile foundation and slab foundation and the like is not the case.

The invention relates to a device for reducing step voltage of a neutral point grounding electrode. The device is characterized in that an insulation grounding conducting wire rod is arranged between a grounding electrode buried underground and a transformer neutral point joint; the insulation grounding conducting wire rod consists of a middle electrical conductor and an insulation external layersurrounding the middle electrical conductor; the end C of the middle electrical conductor of the insulation grounding conducting wire rod is connected with the grounding electrode buried underground,and the end S of the middle electrical conductor of the insulation grounding conducting wire rod is connected with the transformer neutral point joint; and the vertically-buried underground depth of the insulation grounding conducting wire rod is more than or equal to the spanning distance of 0.8m. The device for reducing the step voltage of the neutral point grounding electrode, provided by the invention, has the advantages of being capable of being applied to the grounding systems of various lightning arresters in an extending manner, reducing the step voltage around the grounding wires when the lightning arresters work, and decreasing the harm to people or livestock, caused by the most dangerous areas of the step voltage, to the minimum.

The invention provides a grounding device of a transformer substation containing inlet and outlet cables. The grounding device comprises cable trench support flat steel, indoor leading flat steel, an indoor grounding main line and overlap region tin coatings, wherein the cable trench support flat steel penetrates through a cable trench support stand column, the indoor leading flat steel is in locked connection with the cable trench support flat steel through a first screw, the indoor grounding main line is in locked connection with the indoor leading flat steel through a first screw, and the overlap region tin coatings are arranged between the cable trench support flat steel and the indoor leading flat steel and between the indoor leading flat steel and the indoor grounding main line. The invention discloses the grounding device of the transformer substation containing inlet and outlet cables and a mounting method of the grounding device. According to the invention, since flat steel or a copper stranded wire is used for connecting the grounding device in a cable structure with a transformer substation grounding network, the grounding device in the cable structure can be used for shunting the transformer substation grounding network, thereby reducing the total ground resistance, further reducing the earth current of the transformer substation grounding network and lowering the contact voltage and step voltage of the transformer substation.

The invention relates to a method for laying a direct current grounding pole, which belongs to the grounding technology of electric power system in the field of electrician. The method comprises the following steps of firstly digging a ring-shaped pit with an isosceles trapezoid cross section in soil, paving a coke layer on the bottom of the ring-shaped pit, embedding the direct current groundingpole over the coke layer and laying a coke layer with the same thickness as the below space of the grounding pole over the direct current grounding pole; and then paving an soil layer over the coke layer, paving an insulation layer over the soil layer, and finally back-filling the soil over the insulation layer so as to lead the soil to be flat with the surrounding ground. The method for laying the direct current grounding pole provided by the invention has the advantage that the laying process is simple and easy to be operated, and the step voltage of the direct current grounding pole can bereduced by only adding a layer of insulation layer in the process of paving the direct current grounding pole. The laying method does not enlarge the occupied area of the direct current grounding pole, does not increase the size of the grounding pole, nor increases the construction cost, thereby needing less investment in economy compared with the existing laying method.

The invention relates to a substation grounding grid in frozen earth area and a design method thereof and belongs to the technical field of substation construction. The grounding grid is a mesh structure in which a plurality of horizontal trunk lines and longitudinal trunk lines are connected, and the grounding grid includes a horizontal grounding grid and a sinking grounding grid where the edge of the horizontal grounding grid is bent downwards. The horizontal grounding grid is located in a frozen earth layer. The lowermost end of the sinking grounding grid is located below the frozen earth layer; and the intersections of the horizontal trunk lines and the longitudinal trunk lines are connected with grounding resistors in the downward directions, and the lowermost ends of the grounding resistors extend below the frozen earth layer. The invention optimizes the structure of the grounding grid, and reduces the stepping voltage and the contact potential of the grounding grid, thereby meeting the safety performance requirements of the grounding grid in areas with high soil resistivity and deep seasonal frozen earth. The invention does not need to increase the amount of material of thegrounding grid, does not need to expand the land acquisition area of the grounding grid and does not use additional chemical resistance-reducing substances, and reduces the investment of the project.