RU2097862C1 - Surge voltage protective gear - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: device has nonlinear resistor in the form at least one pile placed in insulating cylinder filled with heat-conducting loose dielectric material. Cylinder is coaxially arranged in cylindrical insulating case in a spaced relation with space filled with heat-conducting loose dielectric material. Device also has vent duct. Insulating barrier is placed in insulating cylinder through its entire height which divides its interior in cross-section into two parts forming, together with inner wall of insulating cylinder, cavity on one end. First part accommodates nonlinear resistor with loose dielectric material and second part, gas vent duct. Barrier may be arc-shaped in section with its convex side facing cavity forming gas vent duct. EFFECT: reduced metal input and size, improved reliability of device. 2 cl, 2 dwg

Description

 The invention relates to electrical engineering and is intended to protect the insulation of high voltage electrical equipment of stations and substations of alternating and direct current from atmospheric and switching overvoltages.

 A device for surge protection (ed. St. 947317, H 01 C l / 028, claim 25.01.78), comprising a non-linear resistor made in the form of parallel columns placed in a cylindrical insulating housing filled with insulating heat-conducting material, and a channel for the release of gases. The gas outlet channel is made in the form of a coaxial insulating body of a two-layer insulating cylinder, and parallel columns are placed between the inner surface of the body and the outer surface of the cylinder.

 This design does not provide the necessary explosion safety, since the arc formed when the resistor columns are blocked in emergency mode and hot gases touching the inside of the porcelain directly or through a small layer of insulating material can cause its destruction as a result of a sharp temperature difference. In addition, in this design, it is necessary to use sufficiently thick-walled porcelain from a high-strength mass, since the strength of ordinary porcelain is insufficient to withstand the internal gas pressure during shutdown until the entire explosion-proof system is activated (inner cylinder valve).

 In addition, the disadvantage of this device is that the cylinder must be circular, which is not rational in terms of obtaining the maximum cross-section of the channel for the exit of gases and the dimensions of the device in the diametrical plane. This is especially pronounced in the case of one or a small number of columns in a nonlinear resistor, when the rest of the space between the cylinder and the housing, except for the location of the column of nonlinear resistors, is unjustified and entails an increase in the dimensions of the device in the diametrical plane and additional material consumption. In addition, in emergency mode, the surface of the insulating cylinder through which hot gases penetrate the gas outlet channel is determined, in practice, by the diametrical section of the damaged column of resistors.

 The specified device is taken as a prototype.

 The invention solves the problem of reducing material consumption, reducing dimensions and increasing the reliability of the device for surge protection.

 The device for surge protection contains a nonlinear resistor made in the form of at least one column, placed in a cylindrical insulating casing in an electrically insulating heat-conducting bulk material, and a gas outlet channel made in the form of an insulating cylinder.

 To solve the problem in this device, a nonlinear resistor is located inside the insulating cylinder, along the entire height of which there is a barrier made of insulating material, dividing its internal cavity into two parts, the first of which contains a nonlinear resistor with bulk electrically insulating heat-conducting material, and in the second channel for gas outlet.

 The partition in cross section may be in the form of an arc and with its convex side facing a part of the cavity with a channel for the exit of gases.

 The combination of these signs allows us to solve the problem of reducing material consumption, reducing the size and increasing the reliability of the device for surge protection.

 In Fig.1 shows a longitudinal section of the device; figure 2 is the same, cross section.

 The device comprises a cylindrical insulating housing 1 with a block 2 located in it, which consists of an insulating cylinder 3 having a partition 4 separating the gas outlet channel 5, and a non-linear resistor 6, made in this case from a single column placed in a loose insulating heat-conducting material 7. In this particular example, the insulating cylinder 3 and the baffle 4 are made of fiberglass, with a cylinder wall thickness of 3 mm and a baffle thickness of 0.5 mm. The partition can be glued into a previously made cylinder 3 or can be technologically performed simultaneously with the execution of the cylinder 3. Quartz sand is used as a heat-conducting insulating bulk material. It also forms a layer 8 between the housing 1 and the cylinder 3. The housing 1 is provided with flanges 9 and sealed with metal covers 10. The covers 10 are made with holes that are closed by safety valves 11.

 Device for surge protection works as follows. In normal operating mode, the device is affected by the operating voltage of the network. When overvoltages occur in the network, the device limits them to a predetermined value in accordance with the current-voltage characteristic of the device. The heat released in this case is removed through the bulk insulating heat-conducting material, the insulating cylinder 3 and the housing 1 to the outside. If damage occurred to the column of non-linear resistor 6, which turned into burning of an arc of a short-circuit current, then in the space where the arc burns, pressure starts to increase sharply, the partition 4 collapses, freeing up a gas outlet for the expansion of hot gases, which it limited. Since this cavity has direct access to the safety valves, the latter, when the pressure reaches the response level, come into action and release the pressure inside the insulating cylinder 3 to the outside. At the same time, the walls of the cylinder 3 and the layer 8 of insulating material protect the housing 1 from direct contact of hot gases and pressure and, as a consequence, from explosive destruction.

 The application of the proposed device design allows the most efficient arrangement of an insulating cylinder, a gas outlet cavity, a nonlinear resistor and heat-conducting insulating material in a cylindrical insulating casing, reducing the dimensions of these elements and, as a result, the dimensions of the entire device, which, in turn, reduces material consumption . The application of the proposed design also increases the reliability of the device, improving explosion safety, and simplifies assembly.

Claims (2)

 1. Device for overvoltage protection, comprising a non-linear resistor made in the form of at least one column placed in a cylindrical insulating casing in an electrically insulating heat-conducting bulk material, and a gas outlet channel made in an insulating cylinder, characterized in that throughout the height of the insulating cylinder there is a partition made of insulating material, dividing its internal cavity into two parts, the first of which contains a nonlinear resistor in a bulk electrical insulation plating material, and in the second specified channel for the exit of gases.  2. The device according to claim 1, characterized in that the partition in the cross section has the shape of an arc and with its convex side facing a part of the cavity with a channel for the exit of gases.

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