CN103208360B - A kind of GIS electronic current-voltage combination transformer - Google Patents

Abstract

The present invention relates to a kind of GIS electronic current-voltage combination transformer, comprise outside vessel shell, for being located in floating potential cylinder in Primary Conductor, floating potential cylinder is equiped with Luo-coil current transformer and coaxial capacitive voltage divider, coaxial capacitive voltage divider comprises high-voltage capacitance and low-voltage capacitance, described coaxial capacitive voltage divider is provided with at least two low-voltage capacitances, and each low-voltage capacitance forms a road and exports.Low-voltage capacitance of the present invention can increase to multiple, and as two, can realize twin voltage instrument transformer sensing head, dual output, the function of two protection, possesses miniaturization, high anti-interference, high accuracy, the advantage such as high reliability, low cost.

Description

A kind of GIS electronic current-voltage combination transformer

Technical field

The present invention relates to a kind of GIS electronic current-voltage combination transformer.

Background technology

Current electronic type voltage transformer many employings capacitance partial pressure structure, as the structure disclosed in the patent documentations such as CN202384167U, CN202384166U.Use the coaxial configuration of primary shielding cover and suspension cylindrical shell as high-voltage capacitance; with the coaxial metal Rotating fields of dielectric as low-voltage capacitance; low-voltage capacitance side also upper resistance is introduced collector, after integration, amplification, double A/D conversion, is converted into light signal after intelligent acess merge cells synchronously processes on measuring and protecting equipment by photoelectric conversion device.

Along with electric power system is to Large Copacity, superhigh pressure and ultra high voltage future development, miniaturized to power equipment, intelligent, the requirement of high reliability is also more and more higher.For national grid, the 110KV level above power station measuring system that intelligent grid proposes is adopted to the principle of two protection, voltage transformer need adopt double-sensing head.

Summary of the invention

The object of this invention is to provide the GIS electronic current-voltage combination transformer that can provide double-sensing head, only have univoltage sensor head in order to solve in prior art, and there is no the problem of twin voltage sensing head electronic mutual inductor.

For achieving the above object, the solution of the present invention is:

A kind of GIS electronic current-voltage combination transformer, comprise outside vessel shell, for being located in floating potential cylinder (7) in Primary Conductor, floating potential cylinder is equiped with Luo-coil current transformer and coaxial capacitive voltage divider, coaxial capacitive voltage divider comprises high-voltage capacitance and low-voltage capacitance, described coaxial capacitive voltage divider is provided with at least two low-voltage capacitances, and each low-voltage capacitance forms a road voltage transformer and exports.

Described low-voltage capacitance is shielded by the intermediate capacitance of coaxial laying successively from inside to outside outside floating potential cylinder and low-voltage capacitance shields, and the dielectric formation between intermediate capacitance screen and low-voltage capacitance screen; Intermediate capacitance screen comprise at least two along same circle distribution, watt shape, nonconducting second metal level (62) mutually, the 3rd metal level (63) that low-voltage capacitance screen is tubular.

Be provided with dielectric between described floating potential cylinder and the second metal level, floating potential cylinder is high-voltage capacitance screen.

Also closely be sticked outside floating potential cylinder the first metal layer (61).

Described each second metal-layer structure, size are all identical.

Each second metal level and the 3rd metal level all form a sensing head interface, connect collecting unit by holding wire.

The present invention by increase separable be multiple electrical isolation part intermediate capacitance shield, for the formation of multiple low-voltage capacitance.Like this, low-voltage capacitance of the present invention just more than, can increase to multiple, as two, can realize twin voltage instrument transformer sensing head, dual output, the function of two protection, possesses miniaturization, high anti-interference, high accuracy, the advantage such as high reliability, low cost.

Accompanying drawing explanation

Fig. 1 (a) is GIS electronic current-voltage combination transformer, and Fig. 1 (b) is partial view;

Fig. 2 is coaxial configuration schematic diagram;

Fig. 3 is resistive-capacitive voltage divider electrical schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the present invention will be further described in detail.

As shown in Figure 1, for single-phase GIS electronic current-voltage combination transformer, its structure is based on traditional SF6 gas-insulated GIS electric current voltage combination transformer structure, outside is vessel shell 4, Luo-coil 10 is fixed in solenoid housing 9, and Luo-coil housing 9 is fixed in vessel shell 4.Primary Conductor 3 and punching Luo-coil composition current sensing head, the signal collected by current sensing head causes collecting unit.Primary Conductor 3, through floating potential cylindrical shell 7, needs insulation processing between floating potential cylindrical shell 7 and vessel shell 4.The corresponding ganged condenser be coaxially located in Primary Conductor, its high-voltage capacitance is by Primary Conductor, floating potential cylinder 7, and the insulating gas between them is formed., floating potential cylinder is high-voltage capacitance screen.High-voltage capacitance screen outside coaxially arranges intermediate capacitance screen and low-voltage capacitance screen from inside to outside successively.Low-voltage capacitance is shielded by intermediate capacitance and low-voltage capacitance shields, and the dielectric between intermediate capacitance screen and low-voltage capacitance screen is formed; Intermediate capacitance screen comprise at least two along same circle distribution, watt shape, nonconducting second metal level mutually, the 3rd metal level that low-voltage capacitance screen is tubular.Dielectric is provided with between floating potential cylinder and the second metal level.High-voltage capacitance screen and intermediate capacitance are shielded and are formed intermediate capacitance with the dielectric between them.Each second metal level and the 3rd metal level all form a sensing head interface, build-out resistor in parallel, form resistive-capacitive voltage divider circuit, and overall formation multihead, can distinguish sampled voltage signal circuit.Collecting unit 1 is connected by holding wire.Collecting unit is arranged on vessel shell 4, exports digital optical signal, exports through optical fiber.Electron collection unit requires to be arranged in the housing of good electromagnetic shielding, improves the operational environment of electronic loop, and reduce electromagnetic interference, power supply is that collecting unit is powered on the spot, overcomes Current Transformer Using Active Compensation Problems existing, and power supply is stable.Export the large resistance of two ends parallel connection at low-voltage capacitance, form high voltage and suppress circuit, at voltage collector input parallel low resistance, ensure voltage signal progress of disease precision.

Second metal level, the 3rd metal level can adopt metal forming, and the dielectric between the second metal level and the 3rd metal level, between floating potential cylinder and the second metal level can adopt engineering plastics.As a kind of execution mode, intermediate capacitance screen and low-voltage capacitance screen can adopt overall three-layer metal paper tinsel 6 to form, infilling work plastics between three-layer metal paper tinsel, first layer metal paper tinsel 61 is closely sticked outside floating potential cylinder, short circuit is conducted electricity with floating potential cylinder, first layer metal paper tinsel and floating potential cylinder form high-voltage capacitance and shield, second metal forming 62 is intermediate capacitance screen, 3rd metal forming 63 is low-voltage capacitance screen, Primary Conductor and high-voltage capacitance are shielded and insulating gas between them forms high-voltage capacitance, high-voltage capacitance screen and intermediate capacitance is shielded and dielectric between them forms intermediate capacitance, intermediate capacitance screen and low-voltage capacitance shields and dielectric between them forms low-voltage capacitance.In the present embodiment, the second metal level is two symmetrical watt shapes.Two the second metal-layer structures, size are all identical, and high-voltage capacitance screen shield with intermediate capacitance, like this formation two low-voltage capacitances.Such overall structure just constitutes a high-voltage capacitance, two intermediate capacitance, two low-voltage capacitances, from two intermediate capacitance number of winning the confidence respectively, two low-voltage capacitance sides, parallel high voltage presses down value bleeder resistance respectively, just constitutes double-sensing head sampled voltage signal respectively.Circuit as shown in Figure 2 and Figure 3.Coaxial capacitance C1 is formed with SF6 gas between Primary Conductor and floating potential cylinder 7,

$c_1=\frac{{2\mathrm{\π\ϵ}}_o{\mathrm{\ϵ}}_{r}l}{1n\frac{b}{a}}---\left(1\right)$

In formula: ε ₀the dielectric constant of relative vacuum; ε _rdielectric constant; L capacitance plate length; A suspension pipe radius; B high-tension shielding radius.Centre fan-shaped (cross section is fan-shaped) coaxial capacitance C2, C2 ' is formed respectively with engineering plastics between the clad with metal foil that high-voltage capacitance screen (first layer metal paper tinsel and suspension positioning pipe) and second layer metal shield into symmetrical mutual two pieces of geometry.The second layer become geometry symmetrical mutually not two pieces of clad with metal foil of electrically conducting and third layer cover metal paper tinsel between with engineering plastics formed respectively low pressure fan-shaped coaxial capacitance C3, C3 ', third layer clad with metal foil earthing potential.Because intermediate capacitance screen and low-voltage capacitance screen are fan-shaped coaxial capacitances, therefore C2, C2 ', C3, C3 ' capacitance can ask, again because second layer clad with metal foil geometry symmetry, therefore, C2=C2 ', C3=C3 '.

According to electrical principle as shown in Figure 3, no-load voltage ratio K1, K2, for:

$k1=k2=\frac{\mathrm{Ui}}{\mathrm{Uo}}=\left|\frac{\mathrm{\α}(1+j{Z}_0\mathrm{\ωC}1)}{j{Z}_0\mathrm{\ωC}1}\right|---\left(2\right)$

In formula

$\mathrm{\α}=\frac{\sqrt{{\mathrm{\ω}}^2{(C_2+C_3)}^2{R}^2+1}}{\mathrm{\ω}{C}_{2}R}$

$Z_0=\frac{\mathrm{j\ωR}(C2+C3)+1}{2(\mathrm{j\ωC}2-{\mathrm{\ω}}^{2}C2C3R)}$

Due to, C1, C2, C2 ', C3, C3 ' all can obtain according to physical dimension, output valve U0=Uo ', build-out resistor R=R ' can ask.

Claims (5)

1. a GIS electronic current-voltage combination transformer, comprise external pressure shell body, for being located in floating potential cylinder (7) in Primary Conductor, floating potential cylinder is equiped with Luo-coil current transformer and coaxial capacitive voltage divider, coaxial capacitive voltage divider comprises high-voltage capacitance and low-voltage capacitance, it is characterized in that, coaxial capacitive voltage divider is provided with at least two low-voltage capacitances, and each low-voltage capacitance forms a road and exports; Described low-voltage capacitance is shielded by the intermediate capacitance of coaxial laying successively from inside to outside outside floating potential cylinder and low-voltage capacitance shields, and the dielectric between intermediate capacitance screen and low-voltage capacitance screen is formed: intermediate capacitance screen comprise at least two along same circle distribution, watt shape, nonconducting second metal level (62) mutually, the 3rd metal level (63) that low-voltage capacitance screen is tubular.

2. a kind of GIS electronic current-voltage combination transformer according to claim 1, is characterized in that, is provided with dielectric between described floating potential cylinder and the second metal level, and floating potential cylinder is high-voltage capacitance screen.

3. according to claim 2 kind of GIS electronic current-voltage combination transformer, is characterized in that, be also closely sticked outside floating potential cylinder the first metal layer (61).

4. a kind of GIS electronic current-voltage combination transformer according to Claims 2 or 3, is characterized in that, described each second metal-layer structure, size are all identical.

5. according to claim 4 kind of GIS electronic current-voltage combination transformer, is characterized in that, each second metal level and the 3rd metal level all form a sensing head interface, connect collecting unit by holding wire.