Environmentally friendly gas-insulated alternating-current metal-enclosed ring network switchgear

Abstract

Disclosed in embodiments of the present application is an environmentally friendly gas-insulated alternating-current metal-enclosed ring network switchgear, comprising a gas tank, a metering compartment, a mechanism compartment, and a cable compartment. A three-position disconnector, copper busbars, copper rods, outlet bushings, and circuit breakers are provided in the gas tank; the gas tank is filled with dry gas; clamping rings are provided at the connections between the copper busbars and the circuit breakers, at isolation knives of the three-position disconnector, and at the connections between the copper rods and the lower outlet bushings and three-position disconnector; and the surface of each clamping ring is provided with a vulcanization layer. In the present application, by means of the design of the clamping rings, the electrode shape is optimized, the electric field intensity is reduced, highly non-uniform electric fields are avoided, the electric field distribution is improved, and partial discharge is strictly controlled, thereby optimizing the electric field distribution, reducing the phase-to-phase and phase-to-ground spacings, and effectively reducing the volume of the gas tank without compromising performance.

Description

Environmentally friendly gas-insulated AC metal-enclosed ring network switchgear Technical Field

[0001] This application relates to the field of switchgear, and more particularly to an environmentally friendly gas-insulated AC metal-enclosed ring network switchgear. Background Technology

[0002] In recent years, some European countries have gradually begun to ban SF6 gas. Furthermore, with the progress made by some large foreign companies in researching SF6 alternatives applicable to high-voltage GIS products, the elimination of SF6 from power transmission and distribution products has become increasingly possible. Because SF6 has 2.5 times the insulation strength of nitrogen at the same pressure, 100 times the arc-extinguishing capacity of air, and 2.3 times the breakdown strength of air in a uniform electric field, maintaining the original SF6-insulated C-GIS switchgear structure and dimensions while simply replacing the gas to meet insulation requirements is extremely difficult.

[0003] Currently, if dry gas is directly used to replace SF6 gas in switchgear on the domestic market, partial discharge may occur. Existing designs mainly address this issue by increasing the phase spacing and ground spacing, but this approach results in a very large gas tank volume, which cannot meet application requirements. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of this application is to provide an environmentally friendly gas-insulated AC metal-enclosed ring network switchgear to optimize the electric field distribution, reduce the phase spacing and the distance to ground, and reduce the volume of the gas box.

[0005] To address the aforementioned technical problems, this application proposes an environmentally friendly gas-insulated AC metal-enclosed ring network switchgear, comprising a gas box, an instrument compartment, a mechanism compartment, and a cable compartment. The gas box contains a three-position disconnect switch, copper busbars, copper rods, outgoing bushings, and a circuit breaker. The gas box is filled with a pre-set dry gas. Pressure rings are provided at the connection points between the copper busbars and the circuit breaker, the disconnecting blades of the three-position disconnect switch, and the connection points between the copper rods and the lower outgoing bushings and the three-position disconnect switch. The surface of the pressure rings is covered with a sulfide layer.

[0006] Furthermore, the maximum allowable electric field strength on the surface of the pressure ring satisfies the following equation:

[0007] Where E2 is the maximum allowable electric field intensity on the surface of the pressure ring, k is a proportionality constant, U is the potential difference between the point of maximum electric field intensity and the low potential of the pressure ring, and P is the geometric characteristic coefficient of the pressure ring. r is the radius of the pressure ring, d is the minimum net distance between the point of maximum electric field strength and the low potential of the pressure ring; α is the first correction factor, ε0 is the dielectric constant of the dry gas; ε rrζ is the relative permittivity of the material of the pressure ring, and ζ is the thickness of the sulfide layer on the surface of the pressure ring.

[0008] Furthermore, α = 1.19.

[0009] Furthermore, insulating skirts are provided at the connection points between the copper busbar and the circuit breaker, and the maximum allowable electric field strength on the surface of the skirts satisfies the following formula:

[0010] E4 is the maximum allowable electric field intensity on the surface of the umbrella skirt, E x E y E z , , respectively, represent the tangential electric fields in the x, y, and z directions at the connection between the copper busbar and the circuit breaker, and β is the second correction coefficient.

[0011] Furthermore, β = 1.53.

[0012] Furthermore, the preset drying gas is dry air.

[0013] The beneficial effects of this application are as follows: This application optimizes the electrode shape, reduces the electric field strength, avoids extremely non-uniform electric fields, improves the electric field distribution, and strictly controls partial discharge by designing the pressure ring, thereby optimizing the electric field distribution, reducing the phase spacing and the distance to ground, and effectively reducing the gas box volume without affecting performance. Attached Figure Description

[0014] Figure 1 is a side view of an environmentally friendly gas-insulated AC metal-enclosed ring network switchgear according to an embodiment of this application.

[0015] Figure 2 is an internal structural diagram of the air box according to an embodiment of this application.

[0016] The attached diagrams are labeled as follows: 10 Gas box, 11 Three-position disconnect switch, 12 Copper busbar, 13 Copper rod, 14 Outgoing bushing, 15 Circuit breaker, 16 Pressure ring, 17 Umbrella skirt, 20 Instrument compartment, 30 Mechanism compartment, 40 Cable compartment. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] In the embodiments of this application, directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0019] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0020] Referring to Figures 1 and 2, the environmentally friendly gas-insulated AC metal-enclosed ring network switchgear of this application embodiment includes a gas box, an instrument room, a mechanism room, and a cable room. The gas box, instrument room, mechanism room, and cable room are existing structures.

[0021] The gas chamber contains a three-position disconnect switch, copper busbars, copper rods, outgoing bushings, and a circuit breaker; this part is part of the existing design. The gas chamber is filled with a pre-set dry gas. The pre-set dry gas is dry air, composed of 79% N2 + 21% O2. This application uses a dry gas with a slight positive pressure of 0.14 MPa as the main insulating medium, reducing gas consumption and resulting in a lower absolute pressure and enhanced safety.

[0022] Pressure rings are provided at the connections between the copper busbar and the circuit breaker, at the isolating blade of the three-position disconnector, and at the connections between the copper rod and the lower outgoing bushing and the three-position disconnector. A sulfide layer is provided on the surface of the pressure rings. This application adds a sulfide layer as an insulation layer, which is equivalent to increasing the insulation distance between conductors, compensating for the loss of clearance due to the addition of the shielding cover.

[0023] As one implementation method, the maximum allowable electric field strength on the surface of the pressure ring satisfies the following equation:

[0024] Where E2 is the maximum allowable electric field intensity on the surface of the pressure ring, k is a proportionality constant (the proportionality constant is a correction parameter that can be obtained by correcting the actual results), U is the potential difference between the maximum electric field intensity point and the low potential point of the pressure ring, and P is the geometric characteristic coefficient of the pressure ring. r is the radius of the pressure ring, d is the minimum net distance between the point of maximum electric field strength and the low potential of the pressure ring; α is the first correction factor, ε0 is the dielectric constant of the dry gas; ε rr Let ζ be the relative permittivity of the material of the pressure ring, and ζ be the thickness of the vulcanized layer on the surface of the pressure ring. In practice, the shape of the pressure ring can be continuously adjusted using the above formula, and the results can be substituted into the formula to determine whether the modification direction is reasonable (if the electric field value increases after the next shape change, it indicates that the modification is unreasonable).

[0025] In one implementation, α = 1.19.

[0026] As one implementation method, insulating skirts are provided at the connection points between the copper busbar and the circuit breaker. The maximum allowable electric field strength on the surface of the skirts satisfies the following formula:

[0027] E4 is the maximum allowable electric field intensity on the surface of the umbrella skirt, E x E y E z Here, ∠x, ∠y, and ∠z represent the tangential electric fields in the x, y, and z directions at the connection point between the copper busbar and the circuit breaker, and β is the second correction coefficient. In practical implementation, the discharge path of the conductor can be blocked by continuously adjusting the sheds using the above formula, preventing the high-potential conductor at this point from directly discharging to the nearest low-potential conductor.

[0028] In one implementation, β = 1.53.

[0029] This application uses the shielding of the umbrella skirt to improve the electric field and reduce the field strength.

[0030] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly gas-insulated AC metal-enclosed ring network switchgear, comprising a gas box, an instrument compartment, a mechanism compartment, and a cable compartment, wherein the gas box contains a three-position disconnect switch, copper busbars, copper rods, outgoing bushings, and a circuit breaker, characterized in that, The gas box is filled with a preset dry gas. Pressure rings are provided at the connection between the copper busbar and the circuit breaker, the isolating knife of the three-position disconnect switch, and the connection between the copper rod and the lower outgoing bushing and the three-position disconnect switch. The surface of the pressure ring is covered with a sulfide layer.

2. The environmentally friendly gas-insulated AC metal-enclosed ring network switchgear as described in claim 1, characterized in that, The maximum allowable electric field strength on the surface of the pressure ring must satisfy the following formula: Where E2 is the maximum allowable electric field intensity on the surface of the pressure ring, k is a proportionality constant, U is the potential difference between the point of maximum electric field intensity and the low potential of the pressure ring, and P is the geometric characteristic coefficient of the pressure ring. r is the radius of the pressure ring, d is the minimum net distance between the point of maximum electric field strength and the low potential of the pressure ring; α is the first correction factor, ε0 is the dielectric constant of the dry gas; ε rr ζ is the relative permittivity of the material of the pressure ring, and ζ is the thickness of the sulfide layer on the surface of the pressure ring.

3. The environmentally friendly gas-insulated AC metal-enclosed ring network switchgear as described in claim 2, characterized in that, α＝1.19。 4. The environmentally friendly gas-insulated AC metal-enclosed ring network switchgear as described in claim 2, characterized in that, Insulating skirts are provided at the connection points between the copper busbar and the circuit breaker. The maximum allowable electric field strength on the surface of the skirts satisfies the following formula: E4 is the maximum allowable electric field intensity on the surface of the umbrella skirt, E x E y E z , , respectively, represent the tangential electric fields in the x, y, and z directions at the connection between the copper busbar and the circuit breaker, and β is the second correction coefficient.

5. The environmentally friendly gas-insulated AC metal-enclosed ring network switchgear as described in claim 4, characterized in that, β＝1.53。 6. The environmentally friendly gas-insulated AC metal-enclosed ring network switchgear as described in claim 1, characterized in that, The preset drying gas is dry air.

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