WO2015172532A1

WO2015172532A1 - Compact main transformer neutral point rod gap lightning arrester and grounding whole-set protecting device

Info

Publication number: WO2015172532A1
Application number: PCT/CN2014/090178
Authority: WO
Inventors: 齐进
Original assignee: 齐进
Priority date: 2014-05-16
Filing date: 2014-11-03
Publication date: 2015-11-19
Also published as: CN203933003U

Abstract

Provided is a compact main transformer neutral point rod gap lightning arrester and grounding whole-set protecting device, comprising: a lightning arrester unit, a rod gap unit, and a grounded blade unit which are connected in parallel. The grounded blade unit comprises a ground blade and a straight-through current transformer (8) used for measuring a neutral point ground current. A rotating shaft (17) of the ground blade is horizontally disposed and is supported by a first bearing seat (13) and a second bearing seat (14) of the ground blade that are directly grounded. One end of the rotating shaft (17) of the ground blade is connected to a conductive rod (7) of the ground blade by means of a connecting hoop (16). The straight-through current transformer (8) is fixedly mounted on a base (6) and is located between the connecting hoop (16) and the first bearing seat (13) of the ground blade. The rotating shaft (17) of the ground blade passes through the straight-through current transformer. An operating crank arm (15) of the ground blade is mounted on the rotating shaft (17) of the ground blade between the first bearing seat (13) and the second bearing seat (14) of the ground blade.

Description

Neutral point bar gap arrester and grounding complete protection device for compact main transformer

Technical field

The invention relates to a transformer protection device, in particular to a compact main transformer neutral point bar gap arrester and a grounding complete protection device.

Background technique

110kV is the main voltage level of the power supply network. Due to the requirements of relay protection setting and prevention of communication interference, in order to limit the single-phase short-circuit current, some of the transformers adopt the neutral point ungrounding method. In this mode of operation, due to lightning strikes, single-phase grounding short-circuit faults, etc., which will cause neutral overvoltage, and the transformers are mostly graded insulation, the overvoltage poses a great threat to the insulation of the neutral point and must be protected. The device prevents accidents.

In the current main transformer neutral point bar gap arrester and grounding protection device, parallel arrester unit, rod gap unit and grounding knife unit are used. There are two main installation methods for this type of structure:

The first type is a four-column structure. As shown in Fig. 1, in the arrester unit, the arrester 5 is mounted on the base 6 through an insulating seat; the rod gap unit is disposed on one side of the arrester unit, and one of the stainless steel rods of the rod gap passes through the insulator. 3 is mounted on the base 6, the upper end is connected to the neutral point of the main transformer, and the other stainless steel rod 2 of the rod gap is installed at the upper end of the vertically disposed supporting steel rod 4, and the supporting steel rod 4 is mounted on the base 6 through the transformer 1 The grounding knife gate unit is disposed on the other side of the arrester unit, and the grounding rod 7 is required to be insulated from the ground, and is grounded through the transformer 8. The GW8 type grounding knife adopts the pillar insulator and an insulated operation link, and the GW13 type ground knife There are two insulators in the structure, and the structure is complicated; therefore, the installation method has a complicated structure, a large volume, and a corresponding manufacturing cost.

The second type is a three-column structure, as shown in FIG. 2, in the arrester unit, the arrester 5 is mounted on the base 6 through the insulating seat; and a stainless steel rod of the rod gap unit is directly mounted on the upper end of the arrester 5, the rod gap The other stainless steel rod pole 2 is mounted on the upper end of the vertically disposed support steel rod 4, and the support steel rod 4 is mounted on the base 6 through the transformer 1. The overall structure is reduced by one insulating column compared to the first one, and the corresponding volume is reduced, and the manufacturing cost is also reduced. However, there are still certain defects: the grounding knife gate unit is the same as the first type of installation, and the structure is complicated; the rod pole of the rod gap unit is directly grounded by the conductor, and the terminal on the arrester cannot apply the power frequency test voltage, so it cannot be directly Measuring the power frequency discharge voltage of the rod gap; due to the difference in the diameter of the rod used as the gap and the form of the gap head, and the environment and altitude of each area are different, the power frequency discharge voltage is highly dispersible, if not at the time of handover The measurement of the discharge voltage is uncertain. In actual operation, the rod gap does not move or moves frequently. In addition, the vertical gap between the rod ground and the charged rod is close, and the spatial stray capacitance is unfavorable to the impulse discharge voltage. influences.

Summary of the invention

The technical problem to be solved by the invention is to provide a compact main transformer neutral point bar gap arrester and grounding complete protection device, capable of performing power frequency discharge voltage test, compact structure, low manufacturing cost, and also capable of avoiding spatial stray capacitance. Adverse effects on the discharge voltage.

In order to solve the above technical problem, the technical solution of the present invention is: a compact main transformer neutral point bar gap arrester and grounding complete protection device, including a parallel arrester unit, a rod gap unit and a grounding knife unit, the innovation is The arrester unit includes a lightning arrester and a counter. The arrester is mounted on the base through an insulator, and the lower end of the arrester is electrically connected to the counter. The rod gap unit includes a first stainless steel rod pole, a second stainless steel rod pole, an insulating column and a conductive row, and the first stainless steel rod pole Directly horizontally mounted on the upper terminal of the arrester, the second stainless steel rod pole is correspondingly disposed on the upper end of the insulating column adjacent to the arrester unit, and the second stainless steel rod pole is connected to the base by the conductive row through the first current transformer; And the conductive row has a horizontal extension at the tail of the second stainless steel rod pole to move the vertical grounding body away from the first stainless steel rod pole; the grounding knife gate unit includes a ground knife and a second ground current for measuring the neutral point Current transformer, the ground knife includes a ground bearing first bearing seat, a ground knife second bearing seat, a ground knife conductive rod The grounding knife rotating shaft, the connecting hoop and the grounding knife operate the turning arm, the grounding knife rotating shaft is horizontally arranged, and is supported by the grounding knife first bearing seat and the grounding knife second bearing seat, and one end of the grounding knife rotating shaft is electrically connected by the connecting hoop and the grounding knife The rod is connected, the first bearing seat of the grounding knife and the second bearing seat of the grounding knife are directly grounded on the base, and the second current transformer is a through-current current transformer, and the second current transformer is fixedly mounted on the base. Between the connecting hoop and the first bearing of the grounding knife, the grounding knife rotating shaft passes through the second current transformer, and the ground knife operating arm is mounted on the ground knife between the first bearing seat of the grounding knife and the second bearing seat of the grounding knife On the shaft.

Preferably, the first current transformer is a feedthrough type current transformer.

The invention has the advantages that: (1) the whole adopts the two-column mounting structure, the structure is compact, the volume is small, and the installation cost can be reduced; the protection of the traditional grounding knife, the transformer, the lightning arrester and the rod gap is a four-column. Structure, which satisfies the functions of neutral grounding, current measurement, gap discharge voltage measurement, overvoltage protection and relay protection, but the construction is complicated and covers a large area. At present, there are some complete sets of devices on the market, which are assembled on a single base, which is a three-column structure. The arrester is used as a pillar of the rod gap. The power frequency discharge voltage test of the rod gap cannot be performed, and the rod length of the gap is long. Shorter (40-50mm), which affects the lightning discharge characteristics of the rod gap, but the length of the mounting base also needs 1.9m; while in the present invention, the base length is only 1.4m, occupying a small area, but the discharge gap is away from the charged body and the grounding body. The distance is increased, which reduces the adverse effect of stray capacitance on the gap electric field distortion, and also enables the measurement of the gap power frequency discharge voltage by the handover and preventive test.

(2) The conductive row has an extending portion in the horizontal direction away from the first stainless steel rod pole at the tail end of the second stainless steel rod pole, increasing the distance between the charged first stainless steel rod pole and the vertical grounding body, reducing the space capacitance to the gap The adverse effects of shock discharge characteristics.

(3) When measuring the bar gap discharge voltage, ground the upper terminal of the arrester, untie the conductive row, and apply a voltage on the second stainless steel rod pole to meet the requirements of the power frequency discharge voltage for the handover and preventive test. The measurability of the device.

(4) The second current transformer is a through-core type, and the rotating shaft of the grounding knife passes through but does not contact, and the position of the second current transformer fixedly mounted on the base is at the connection of the grounding knife conductive rod and the grounding knife rotating shaft Between the hoop and the first bearing of the grounding knife, the grounding knife rotating shaft passes through the second current transformer, and the grounding knife operating arm is mounted on the grounding knife rotating shaft between the first bearing seat of the grounding knife and the second bearing seat of the grounding knife The arrangement of the second current transformer and the first bearing seat of the grounding knife avoids the influence of the shunting of the grounding knife bearing on the current measurement, so that the grounding bearing housing and the grounding knife operating arm can be directly grounded, and there is no insulation requirement for the grounding knife bearing. The structure of the line ground knife is suitable for the neutral point ground knife; the line ground knife does not need to measure the ground current, and the common type of neutral point ground knife GW13 type and GW8 type require the cutter rod to be insulated from the ground because of the current measurement method, By adopting the simple structure of the line ground knife, the invention avoids the insulation problem by changing the structure and the installation position of the current transformer, simplifies the structure of the neutral point knife, and makes the line ground knife and the neutral point ground knife parts common, simplifying the simplification. Ground Type.

DRAWINGS

Figure 1 is a schematic view showing the structure of a conventional protection device for a neutral point bar gap, a lightning arrester, a current transformer and a grounding knife.

Figure 2 is a schematic diagram of the structure of the main transformer neutral point bar gap arrester and grounding protection device in the market.

FIG. 3 is a structural schematic view of a neutral main transformer neutral point bar gap arrester and a grounding complete protection device according to the present invention.

Fig. 4 is a view taken along the line A in Fig. 3;

detailed description

3 and 4 show a compact main transformer neutral point bar gap arrester and grounding protection device of the structure of the present invention, which comprises a parallel arrester unit, a rod gap unit and a grounding knife unit; wherein

The arrester unit includes a lightning arrester 5 and a counter. The arrester 5 is mounted on the base 6 through the insulator 11, and the lower end of the arrester 5 is electrically connected to the counter.

The rod gap unit comprises a first stainless steel rod pole 10, a second stainless steel rod pole 2, an insulating column 12 and a conductive row 9. The first stainless steel rod pole 10 is directly horizontally mounted on the upper terminal of the arrester 5, and the second stainless steel rod pole 2 corresponds to The second stainless steel rod 2 is connected to the upper end of the first current transformer 1 through the conductive row 9 at the upper end of the insulating column 12 on one side of the arrester unit; and the conductive strip 9 has a horizontal level at the tail of the second stainless steel rod 2 In the direction and away from the extension of the first stainless steel rod pole, the extension function is to increase the distance between the charged rod and the vertical grounding body, and reduce the adverse effect of the space capacitance on the gap discharge characteristics.

The ground knife comprises a ground knife first bearing seat 13, a ground knife second bearing seat 14, a ground knife conductive rod 7, a ground knife shaft 17, a connecting hoop 16 and a ground knife operating arm 15, and the ground knife shaft 17 is horizontally disposed, and Supported by the ground knife first bearing seat 13 and the ground knife second bearing seat 14, one end of the ground knife shaft 17 is connected with the ground knife conductive rod 7 through the connection hoop 16, the ground knife first bearing seat 13 and the ground knife second bearing The seat 14 is directly grounded on the base 6, and the second current transformer 8 is a feedthrough type current transformer. The second current transformer 8 is fixedly mounted on the base 6 at a position of the connection hoop 16 and the ground knife first bearing. Between the seats 13, the grounding shaft 17 is passed through the second current transformer 8, and the grounding knife arm 15 is mounted on the grounding shaft 17 between the first bearing seat 13 and the second bearing 14 of the grounding knife. .

The arrangement of the second current transformer 8 and the ground bearing first bearing block 13 avoids the influence of the shunt bearing shunt on the current measurement, so that the ground bearing housing and the ground knife operating arm can be directly grounded.

The first current transformer is a through-current current transformer. In the neutral point protection device currently used, the first and second current transformers are replaced by line current transformers, and the insulation level at the inlet and outlet ends is 10-35 kV. Large, high cost is a waste. Since the ground current is measured, the primary and secondary windings are equipotentially grounded, and the iron core of the transformer is directly connected to the base, and the secondary winding insulation level design of the first current transformer and the second current transformer only needs to consider two The open circuit voltage that the secondary winding may withstand, therefore, the invention adopts a through-core transformer with a power frequency withstand level of 1500V, and the volume of the transformer is small, which can meet the requirements of the same axial installation mode as the ground bearing housing.

Claims

A compact main transformer neutral point bar gap arrester and grounding complete protection device, comprising a parallel arrester unit, a rod gap unit and a grounding knife unit, characterized in that:

The arrester unit includes a lightning arrester and a counter, the arrester is mounted on the base through an insulator, and the lower end of the arrester is electrically connected to the counter;

The rod gap unit comprises a first stainless steel rod pole, a second stainless steel rod pole, an insulating column and a conductive row, the first stainless steel rod pole is directly horizontally mounted on the upper terminal of the arrester, and the second stainless steel rod pole is correspondingly disposed adjacent to the arrester unit The upper end of the insulating column on one side, the second stainless steel rod pole is connected to the base by the conductive row through the first current transformer; and the conductive row has a horizontal extension at the tail of the second stainless steel rod pole to make the grounding vertical The body is away from the first stainless steel rod pole;

The grounding knife gate unit comprises a grounding knife and a second current transformer for measuring a grounding current of the neutral point, the grounding knife comprises a grounding knife first bearing seat, a grounding knife second bearing seat, a grounding knife conductive rod, a grounding knife rotating shaft, and a connection The hoop and the ground knife operate the arm, the grounding shaft is horizontally arranged, and is supported by the first bearing seat of the grounding knife and the second bearing seat of the grounding knife, and one end of the rotating shaft of the grounding knife is connected with the conductive rod of the grounding knife through the connecting hoop, the grounding knife The first bearing seat and the second bearing seat of the grounding knife are directly grounded on the base, and the second current transformer is a through-current current transformer, and the second current transformer is fixedly mounted on the base at a position of connecting the hoop and the ground. Between the first bearing seats of the knives, the grounding knife rotating shaft passes through the second current transformer, and the ground knives operating arm is mounted on the grounding knife rotating shaft between the first bearing seat of the grounding knife and the second bearing seat of the grounding knife.
The compact main transformer neutral point bar gap arrester and grounding protection device according to claim 1, wherein the first current transformer is a feedthrough type current transformer.