CN111384709A - A high-voltage and large-capacity split reactance current limiter - Google Patents

Abstract

A high-voltage and large-capacity split reactance type current limiter adopts a three-phase independent structure. The single-phase split reactor type current limiter is composed of a single high-voltage split reactor and a single multi-break fast vacuum circuit breaker, and the multi-break fast circuit breaker is located on one arm of the split reactor. The high-voltage split reactor consists of an inner reactor winding, an outer reactor winding and an insulating baffle; both the inner reactor winding and the outer reactor winding adopt a multi-encapsulated parallel dry-type air-core reactor structure. The windings of the reactor windings are wound in opposite directions, the inlet end at the bottom shares a terminal, the outlet ends at the top are independent of each other, the outlet end (1) at the top of the inner reactor winding is inside the inner reactor winding, and the outer end of the outer reactor winding The outlet end (2) is on the outside of the outer reactor winding, the inner reactor winding and the outer reactor winding are separated by an insulating baffle, and the height of the insulating baffle is higher than that of the inner reactor winding and the outer reactor winding.

Description

A high-voltage and large-capacity split reactance current limiter

technical field

The invention relates to a split reactance type current limiter applied to short-circuit fault current limiting.

Background technique

With the rapid development of the national economy, the level of short-circuit current in power grids at all levels continues to increase, and the insufficient breaking capacity of short-circuit current in power grid faults has increasingly become an important bottleneck restricting the development of power grids. Considering the insufficient breaking capacity of circuit breakers, the solution of installing fault current limiters in the grid has received extensive attention. The fault current limiter has a small impedance under normal conditions, and the impedance becomes large to limit the current during a short-circuit fault. The current fault current limiter technologies mainly include split reactance current limiters, series resonant current limiters, solid state current limiters and other current limiting technologies realized by conventional power devices, as well as superconducting current limiters, PTC thermistor limiters, etc. The current limiting technology implemented by the application of new materials such as the current device.

Considering the insufficient breaking capacity of existing high-voltage large-capacity mechanical switches and power electronic switches, and the immature fault current limiter technology, if a large-capacity circuit breaker or current limiter can be constructed in a very cheap way at present, it will has a very positive meaning. In order to reduce the current flowing through the switching device, Chinese invention patent 200610011904.X published a superconducting fault current limiter based on split reactor, Chinese invention patents 200710052947.7 and 201210252205.X respectively disclosed parallel circuit breaker based on split reactor A series resonant current limiter based on a split reactor is disclosed in Chinese invention patent 201310007027.9. The protection content of the above-mentioned patents only relates to the circuit topology, and does not relate to the specific split reactor structure. Invention patents 200810197118.2 and 200910208943.2 disclose the structure of a close-coupled air-core reactor applied to a parallel circuit breaker. The high-coupling air-core split reactor adopts a coaxially arranged first winding and a second winding. The encapsulations are arranged in turn from the inside to the outside, and any two encapsulations, as well as between the encapsulation and the wiring arm, must bear twice the overvoltage during the current-limiting breaking. In the current limiting state, the port voltage of the tightly coupled reactor is twice the current limiting voltage of the reactor. The utility model patents 201220373229.6, 201620340866.1 and 201721528069.7 respectively disclose the new structure and outlet method of the tightly coupled reactor, which can tighten the current limiting state. The port voltage of the coupling reactor is reduced by half. However, each encapsulation generally adopts the epoxy casting process, which is high in cost, low in pressure resistance, poor in heat dissipation, and easy to be aged in outdoor applications, so it is difficult to directly apply to outdoor occasions. When the reactor with epoxy casting structure is used in outdoor applications, a rain cover is usually used on the top and periphery of the reactor, which further reduces the heat dissipation capacity. Invention patent 201410117670.1 proposes a split reactor with a double-column structure, which can be hollow, iron core or semi-iron core structure. The coil adopts epoxy casting or oil-immersed structure, and the port voltage of the split reactor can also be reduced by half. The epoxy casting structure is generally used for a maximum voltage level of 35kV, and it is difficult to use in outdoor applications. The oil-immersed structure has low winding strength and poor safety under the impact of high voltage and high current.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the existing splitting reactor, such as low port withstand voltage, requiring multiple modules to be connected in series, and occupying a large area, and to propose a high-voltage and large-capacity splitting reactor type current limiter. In the present invention, a single branch of the high-voltage splitting reactor is connected in series with the multi-break fast circuit breaker, and then the series-connected branch is connected in parallel with another branch of the high-voltage splitting reactor to reduce the breaking capacity of the circuit breaker to less than the short-circuit capacity. 50%. At the same time, when the circuit breaker is disconnected, the impedance of the high-voltage splitting reactor increases rapidly, and the fault current is quickly limited, which is beneficial to the effective disconnection of the fault line by the main circuit breaker of the system. The high-voltage split reactance type current limiter of the present invention has relatively high withstand voltage at the ports of the split reactor and multi-break circuit breakers, and occupies a small area. A single current limiter can be used for voltage levels of 220kV and above. It can be used in high-voltage and ultra-high-voltage power grid systems.

In order to achieve the above object, the present invention adopts the following technical solutions:

The split reactance type current limiter of the present invention adopts a three-phase independent structure, and the single-phase split reactance type current limiter is composed of a single high-voltage split reactor and a single multi-break fast circuit breaker, and the multi-break fast circuit breaker is located at the side of the split reactor. On one arm, split reactance type current limiters are connected in series in the grid through conventional circuit breakers.

The high-voltage split reactor consists of an inner reactor winding, an outer reactor winding and an insulating baffle. The inner reactor winding, the outer reactor winding and the insulating baffle are coaxially arranged, and the insulating baffle is located between the inner reactor winding and the outer reactor. between the reactor windings. Both the inner reactor winding and the outer reactor winding adopt a multi-encapsulated dry type air-core reactor structure. The winding directions of the inner reactor winding and the outer reactor winding are opposite, and the inner reactor winding and the outer reactor winding are at the incoming line end at the bottom. A terminal is shared, and the outlet ends at the top are independent of each other. The outlet end at the top of the inner reactor winding is inside the inner reactor winding, and the outlet end at the top of the outer reactor winding is outside the outer reactor winding; the inner reactor winding is connected to the outer reactor winding. Insulation baffles are used to isolate the reactor windings to prevent breakdown and creepage discharge between the outer side of the reactor winding and the inner side of the outer reactor winding in the current limiting state. The short-time impulse withstand voltage that a single high-voltage split reactor port can withstand can reach more than 400kV, and a single split reactor type current limiter of the present invention can be used for voltage levels of 220kV and above.

The encapsulation of the inner reactor winding and the outer reactor winding can be wrapped with pre-impregnated glass cloth or epoxy pouring structure; the wiring arm at the bottom of the inner reactor winding and the outer reactor winding adopts an integrated star arm structure , the wiring arm at the top of the inner reactor winding adopts a star-shaped arm structure, and the wiring arm at the top of the outer reactor winding adopts a star-shaped arm structure with an inner ring; the operating mechanism of the multi-break fast circuit breaker adopts an electromagnetic repulsion mechanism, which adopts a set of The mechanism breaks multiple fractures at the same time.

The present invention has the following advantages:

1) The split reactor type current limiter of the present invention has a simple structure, is easy to implement, and has high reliability. During normal operation, the split reactor has a small impedance, which has little impact on the system, and starts when the fast circuit breaker is not disconnected. To a certain extent to suppress the short-circuit current, when the fast circuit breaker is disconnected, the impedance of the split reactor increases rapidly, thereby effectively limiting the short-circuit current.

2) The present invention can be used to construct a high-pressure and large-capacity restrictor. Because the high-voltage split reactor adopts a high-port withstand voltage insulation structure with long distance between the incoming and outgoing lines, the port distance between the two outgoing lines and the creepage distance, there is no need to use a rain cover, and the short-term power frequency withstand voltage that the port can withstand is up to Above 400kV, there is no need to use the structure of multiple split reactors and multiple fast circuit breakers in series, with small footprint and low price.

Description of drawings

Figure 1 is an equivalent circuit diagram of a multi-module split reactance current limiter;

Fig. 2 is the equivalent circuit diagram of the high-voltage large-capacity split reactance type current limiter of the present invention;

3 is a schematic structural diagram of an existing high-coupling splitting reactor;

FIG. 4 is a schematic structural diagram of a high-voltage splitting reactor of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Figure 1 shows the equivalent circuit diagram of a conventional multi-module split reactance current limiter. As shown in Figure 1, the multi-module split reactor type current limiter is composed of a plurality of high-coupling split reactor modules and a plurality of fast circuit breaker modules.

FIG. 2 is an equivalent circuit diagram of an embodiment of a high-voltage large-capacity split-reactance-type current limiter of the present invention. As shown in Figure 2, the high-voltage split reactor type current limiter is composed of a high-voltage split reactor and a multi-break fast circuit breaker. The high-voltage splitting reactor adopts the coil structure and outlet method with high port withstand voltage; the operating mechanism of the multi-break fast circuit breaker adopts the electromagnetic repulsion mechanism, and a set of mechanism is used to open multiple fractures at the same time.

FIG. 3 is a schematic structural diagram of a conventional high-coupling splitting reactor. As shown in Figure 3, the high-coupling split reactor adopts the first winding and the second winding arranged coaxially, and the encapsulation of the first winding and the second winding are arranged in turn from the inside to the outside. As well as the overvoltage between the package and the wiring arm during current-limiting interruption. Therefore, each encapsulation generally adopts the epoxy casting process, which has high cost and low pressure resistance, and is difficult to apply to outdoor occasions.

FIG. 4 is a schematic structural diagram of a high-voltage splitting reactor of the present invention. As shown in Figure 4, the high-voltage split reactor of the present invention is composed of an inner reactor winding, an outer reactor winding and an insulating baffle. The inner reactor winding, the outer reactor winding and the insulating baffle are coaxially arranged, and the insulating baffle is located in the inner reactor. Between the reactor winding and the outer reactor winding; the inner reactor winding and the outer reactor winding both adopt the multi-encapsulated dry type air-core reactor structure, the winding direction of the inner reactor winding and the outer reactor winding are opposite, and the inner reactor winding It shares a terminal with the outlet end of the outer reactor winding at the bottom. The outlet ends at the top are independent of each other. The outlet end 1 at the top of the inner reactor winding is inside the inner reactor winding, and the outlet end 2 at the top of the outer reactor winding is outside. On the outside of the reactor winding, there is a port insulation distance of more than 0.5m between the outlet end 1 and the outlet end 2; the inner reactor winding and the outer reactor winding are separated by an insulating baffle, the thickness of the insulating baffle is more than 1cm, and the insulating baffle The height of the board is more than 0.5m higher than that of the inner reactor winding and the outer reactor winding, leaving a creepage distance of more than 1m to prevent breakdown and breakdown between the outer side of the inner reactor winding and the inner side of the outer reactor winding in the current limiting state. Discharge along the surface. The short-term impulse withstand voltage of the high-voltage splitting reactor can reach more than 400kV; the high-voltage splitting reactor, the encapsulation of the inner reactor winding and the outer reactor winding can adopt the pre-impregnated glass fiber cloth winding structure; the inner reactor winding and the outer reactor winding The wiring arm at the bottom of the winding adopts an integrated star arm structure, the wiring arm at the top of the inner reactor winding adopts a star arm structure, and the wiring arm at the top of the outer reactor winding adopts a star arm structure with an inner ring.

Claims (5)

1. A high-voltage high-capacity split reactance type current limiter is characterized in that: the single-phase split reactance type current limiter consists of a single high-voltage split reactor and a single multi-break quick breaker, and the multi-break quick breaker is positioned on one arm of the split reactor; the split reactance type current limiter is connected in series in a power grid through a conventional circuit breaker;

the high-voltage split reactor comprises an inner reactor winding, an outer reactor winding and an insulating baffle; the inner reactor winding and the outer reactor winding are both in a multi-package parallel dry type air-core reactor structure, the winding directions of the inner reactor winding and the outer reactor winding are opposite, the wire inlet ends of the inner reactor winding and the outer reactor winding at the bottom share one wiring terminal, the wire outlet ends at the top are mutually independent, the wire outlet end (1) at the top of the inner reactor winding is arranged at the inner side of the inner reactor winding, and the wire outlet end (2) at the top of the outer reactor winding is arranged at the outer side of the outer reactor winding; the inner reactor winding and the outer reactor winding are isolated by an insulating baffle to prevent breakdown and creeping discharge between the outer side of the reactor winding and the inner side of the outer reactor winding in a current limiting state.

2. A high voltage high capacity split reactance type current limiter according to claim 1 characterized by: and a port insulation distance larger than 0.5m is reserved between the outlet end (1) at the top of the inner reactor winding and the outlet end (2) at the top of the outer reactor winding.

3. A high voltage high capacity split reactance type current limiter according to claim 1 characterized by: the thickness of the insulating baffle is more than 1cm, the height of the insulating baffle is more than 0.5m higher than that of the inner reactor winding and the outer reactor winding, and a creepage distance of more than 1m is reserved.

4. A high voltage high capacity split reactance type current limiter according to claim 1 characterized by: the short-time impact voltage withstanding capability of the single splitting reactor port can reach more than 400kV, and the single high-voltage splitting reactance type current limiter can be used for voltage classes of 220kV and more than 220 kV.

5. A high voltage high capacity split reactance type current limiter according to claim 1 characterized by: each parallel envelope of the inner reactor winding and the outer reactor winding adopts a preimpregnated glass fiber cloth winding structure; the connection arms at the bottoms of the inner reactor winding and the outer reactor winding adopt an integrated star-shaped arm structure, the connection arm at the top of the inner reactor winding adopts a star-shaped arm structure, and the connection arm at the top of the outer reactor winding adopts a star-shaped arm structure with an inner ring; the operating mechanism of the multi-fracture quick breaker adopts an electromagnetic repulsion mechanism, and a set of electromagnetic repulsion mechanism is adopted to simultaneously break a plurality of fractures.

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