CN102377173A

CN102377173A - Novel bridge circuit type high-temperature superconducting fault current limiter

Info

Publication number: CN102377173A
Application number: CN2010102650538A
Authority: CN
Inventors: 张绪红; 尹小红; 朱鹰屏
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-08-19
Filing date: 2010-08-19
Publication date: 2012-03-14

Abstract

The invention discloses a novel bridge circuit type high-temperature superconducting fault current limiter which comprises a load switch FOLS, a superconducting inductor L and a bias power supply which are successively connected on a bridge in series, wherein a solid switch SSTS and a current limiting resistance R2 are connected in series, and then one end of the solid switch SSTS and the current limiting resistance R2 is connected with the positive polarity end of the bias power supply, and the other end is connected with the connecting point of the load switch FOLS and the superconducting inductor L. When a power grid is failed in short trouble, the novel bridge circuit type high-temperature superconducting fault current limiter can limit the peak value of the fault current and can limit the steady-state value of the fault current, has obvious current limiting effect and can be applied to short trouble current limitation of a power grid system.

Description

Novel bridge circuit type high temperature superconducting malfunction current limiter

Technical field

The present invention relates to a kind of fault current limiter, particularly a kind of novel bridge circuit type high temperature superconducting malfunction current limiter.

Background technology

Expansion day by day along with the scale of electrical network under the extra high voltage system failure condition, can produce very large fault current; Existing primary cut-out is difficult to excise short-circuit current, in order to reduce fault current, many current limiters occurred; Power electronics flow restricter for example; Reactance current limiter and split reactor etc., comparatively ideal is superconductive current limiter, development at present is bridge circuit type high temperature superconducting malfunction current limiter faster.

The structure of basic bridge circuit type high temperature superconducting malfunction current limiter is as shown in Figure 1; The current-limiting circuit that superconduction inductance and bias supply are composed in series is set in electric bridge; It utilizes the inductance of superconducting coil to come fault current limiting; Cooperate rectifier bridge that the adjusting of continuous current circuit is controlled through superconducting magnet and realize current limliting, and operating current is easy to adjust.The defective of this fault current limiter is: 1) but it is the induction reactance current limliting in itself, be the thermal energy storage process of inductance, and peak value that can only fault current limiting, very not obvious to the restriction of stable state fault current.2) Dc bias in the rectifier bridge of bridge circuit type high temperature superconducting malfunction current limiter can reduce the limitation capability of short circuit current when short trouble.

Summary of the invention

In order to solve the technical problem that existing bridge circuit type high temperature superconducting malfunction current limiter exists, the present invention proposes a kind of simple in structure, the peak value that can fault current limiting and the novel bridge circuit type high temperature superconducting malfunction current limiter of steady-state value.

The technical scheme that the present invention solves the problems of the technologies described above is: comprise an electric bridge; The current-limiting circuit that one superconduction inductance and bias supply are composed in series is set on electric bridge; It is characterized in that: on-load switch FOLS, superconduction inductance L and bias supply are serially connected on the electric bridge successively, solid-state switch SSTS and current-limiting resistance R ₂Serial connection back one termination bias supply Ub positive ends, the tie point of another termination on-load switch FOLS and superconduction inductance L.

Technique effect of the present invention is: 1) the present invention breaks off the dc offset voltage source when the electrical network failed because, avoids the influence of dc bias current to the limitation capability of fault current, has improved the effect of current limliting.2) when short trouble, superconduction inductance of the present invention directly seals in without rectifier bridge, and with current-limiting resistance series connection current limliting, but but the not only peak value of fault current limiting but also the steady-state value of fault current limiting have improved the effect of current limliting.3) and because the short trouble energy mainly consumes in current-limiting resistance, rather than consume on the superconduction inductance, thereby greatly reduce the power rank and the operating cost of cryogenic system.4) in the system restoration process, superconduction inductance and current-limiting resistance series connection form the discharge loop of superconduction inductance, can guarantee that the superconduction inductance returns to normal value in 0.5 cycle, have the high-speed reclosure performance.5) the present invention only current waveform occurs at transcient short circuit time and jumps in the short trouble process, and the time thereafter, distortion does not appear in current waveform.

Below in conjunction with accompanying drawing the present invention is further described.

Description of drawings

Fig. 1 is the schematic diagram of basic bridge circuit type high temperature superconducting malfunction current limiter.

Fig. 2 is a schematic diagram of the present invention.

Fig. 3 is a schematic diagram of the present invention.

Embodiment

Referring to Fig. 2, Fig. 2 is a schematic diagram of the present invention.On-load switch FOLS, superconduction inductance L and bias supply are serially connected on the electric bridge successively among the present invention, solid-state switch SSTS and current-limiting resistance R ₂Serial connection back one termination bias supply Ub positive ends; The tie point of another termination on-load switch FOLS and superconduction inductance L; Be lower than 100 μ s the operate time of on-load switch FOLS and solid-state switch SSTS, all satisfy the requirement of electric power system reclosing, and increased current-limiting resistance R ₂Be used for failure current limit.

The operation principle of novel bridge circuit type high temperature superconducting malfunction current limiter: under the normal running (operation) conditions, on-load switch FOLS is closed, and solid-state switch SSTS breaks off, and resistance R 2 does not have galvanization, and operating state is identical with basic bridge circuit type HTSCFCL.When bias current was higher than the peak value of normal current, the current limliting phenomenon did not appear in flow restricter.

When breaking down, the peak value of fault current is more than or equal to bias current, and superconducting coil is automatically connected into circuit, utilizes current limit by inductance.Solid-state switch SSTS and on-load switch FOLS detect fault information; Solid-state switch SSTS is automatic closing in 80 μ s; On-load switch FOLS breaks off (closing time of solid-state switch SSTS is adjusted is the opening time less than on-load switch FOLS, in case solid-state switch SSTS produces electric arc) in 100 μ s.This moment, direct current biasing power supply Ub was out of service, and current-limiting resistance R2 seals in the circuit current limliting, can reduce fault current, improves the current limiting capacity of flow restricter.In the current limliting process, the short trouble energy mainly consumes on current-limiting resistance R2, rather than consumes on the superconduction inductance, thereby greatly reduces the loss of cryogenic system.In the system restoration process, superconduction inductance and current-limiting resistance R2 series connection form discharge loop, can guarantee that the superconduction inductance returns to normal value in 0.5 cycle.Because have the needs of quick doubling force System Expansion all less than 100 μ s the operate time of solid-state switch SSTS and on-load switch FOLS.The lock performance.Can select the value of current-limiting resistance R2 flexibly, to satisfy the needs of electric power system dilatation.

Require not current limliting of flow restricter under the normal condition, the present invention is identical with the operation principle of basic bridge circuit type high temperature superconducting malfunction current limiter.Flow restricter is wanted current limliting during failure condition; When failure condition line current peak value is equal to or greater than bias current I0; Current waveform sketch map such as Fig. 3 in line current and the diode (ignoring discharging and recharging and phase deviation of inductance); Electric current in the diode ends less than 0 pair of diodes, and another is to diode current flow, and superconducting coil L is automatically connected into current limliting.It is thus clear that bias current is big more, the diode barrier portion is more little, and the part that superconducting coil seals in current limliting is more little.Therefore bias current is big more, and current limitation effect is poor more.The present invention is out of service with direct current biasing power supply Ub at failure condition.

Claims

1. novel bridge circuit type high temperature superconducting malfunction current limiter; Comprise an electric bridge; The current-limiting circuit that one superconduction inductance and bias supply are composed in series is set on electric bridge; It is characterized in that: on-load switch FOLS, superconduction inductance L and bias supply are serially connected on the electric bridge successively, solid-state switch SSTS and current-limiting resistance R ₂Serial connection back one termination bias supply Ub positive ends, the tie point of another termination on-load switch FOLS and superconduction inductance L.