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Parallel resonance short-circuit fault current limiter with series compensating function

A series compensation and short-circuit fault technology, which is applied in the direction of emergency protection circuit devices, circuit devices, emergency protection circuit devices, etc. for limiting overcurrent/overvoltage, can solve the problems of large operating loss, high operating costs, and high cost. Achieve the effect of increasing the voltage at the end of the line, limiting the short-circuit current, and reducing voltage loss

Inactive Publication Date: 2009-12-23
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantages are: due to the high voltage and large current of the power system, control components (such as rectifiers, thyristors, GTO, etc.) need to be connected in series and parallel, resulting in high cost, complicated control, large volume and weight, and large operating loss, etc.
The main disadvantages are: high cost, high operating costs due to cooling, and complex coordination with existing circuit breakers and relay protection in the power system, etc.
The main disadvantages are: PTC resistors are more easily affected by external factors; the overvoltage problem is more serious during current limiting; because the rated voltage and rated current of a single PTC resistor element are not large, it is necessary to combine multiple elements in series and parallel in the power system Formed, resulting in high cost, complicated control, large volume and weight, etc.
For this reason, the current fault current limiter is generally connected in parallel with a bypass reactor next to the fault current limiter in order to cooperate with the existing line relay protection, resulting in a larger volume and weight of the entire device, and a higher cost

Method used

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  • Parallel resonance short-circuit fault current limiter with series compensating function
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  • Parallel resonance short-circuit fault current limiter with series compensating function

Examples

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Embodiment 1

[0019] The current limiter circuit of the present invention is as figure 1 shown. Among them: 1 is the compensation capacitor C, 2 is the transformer T, 3 is the solid-state control switch V, 4 is the current limiting resistor R. The primary side of the transformer 2 is connected in parallel with the capacitor 1 , and the secondary side of the transformer 2 is connected in parallel with the series circuit composed of the current limiting resistor 4 and the solid state switch 3 . The current limiter of the present invention is connected in series in the circuit of the power system through M and N ports.

[0020] The wiring diagram of the current limiter of the present invention in the power system is as follows: figure 2 shown. Among them, the equivalent power supply of the power system is G, and the equivalent internal impedance of the power supply is r S +jx S , DL is a circuit breaker, and the equivalent impedance of the transmission line is r L +jx L , load equivale...

Embodiment 2

[0051] Such as figure 1 shown. The solid-state switch V in the current limiter of the present invention can choose high-power controllable devices such as silicon controlled rectifiers and GTOs. The devices for detecting and judging the occurrence of short-circuit faults in the power system, detecting and judging the disappearance of short-circuit faults in the power system, and controlling solid-state switching devices are well known, so the current limiter of the present invention will not describe them in detail. Due to the transformation ratio of the transformer T to the equivalent circuit (such as image 3 , Figure 5 ) in r, r 2 、jx 2 The influence is greater, so the transformation ratio must be considered when designing and selecting the transformer T. A suitable transformation ratio can also reduce the secondary side voltage of the transformer T when the power system fails, and thus reduce the cost of the solid-state switch V.

Embodiment 3

[0053] Such as figure 2 As shown, the current limiter of the present invention is connected to the head end of the transmission line that needs current limiting, behind the circuit breaker DL at the head end of the line.

[0054] For a single-phase power system, the transformer T in the current limiter of the present invention is a single-phase double-winding transformer.

[0055] For a three-phase power system, the transformer T of the current limiter of the present invention is a three-phase double-winding transformer, and there are three capacitors C, which are respectively connected in parallel on the primary side A, B, and C phases of the transformer T; the current limiting resistor R and the solid state There are also three series circuits composed of switches V, which are connected in parallel to the phases a, b, and c of the secondary side of the transformer T respectively.

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PUM

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Abstract

The invention relates to a parallel resonance short-circuit fault current limiter with series compensating function, belonging to the technical field of flexible alternating current transmission. The value of the power system short-circuit fault current is improved continuously, and the damage of the short-circuit fault to the power system and electric equipment connected therewith are larger and larger. Currently, large short-circuit current is one of important factors for restricting the operation and development of the power grid, and the limiting of the short-circuit current of the power system is important problem. The parallel resonance short-circuit fault current limiter consists of a compensating capacitor C, a transformer T, a current-limiting resistor R and a solid control switch V. When the power system operates normally, the parallel resonance short-circuit fault current limiter has the series compensation function as a series capacitor on the line reactance. By means of a compensation part of the series compensation capacitor or all line inductance, the parallel resonance short-circuit fault current limiter reduces voltage loss generated in a reactive current in a power grid, improves the voltage at the tail end of the line, and simultaneously improves the operation stability of the system. When the power system is in failure, the fault current limiter generates parallel resonance by the closing of the solid switch V, thus limiting the short-circuit current.

Description

technical field [0001] The invention relates to a fault current limiter for limiting the short-circuit current of a power system, in particular to a parallel resonance type short-circuit fault current limiter with a series compensation function, which belongs to the technical field of flexible AC transmission. Background technique [0002] With the expansion of the capacity and scale of the power system, the value of the short-circuit fault current of the power system is also continuously increasing. The large short-circuit current has become one of the important factors restricting the operation and development of the power grid. Limiting the short-circuit current of the power system has become an important issue. For this reason various types of fault current limiters began to appear. [0003] At present, fault current limiters are mainly divided into two categories: the first category is a current limiter that uses power electronic devices to control line impedance; the s...

Claims

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Application Information

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IPC IPC(8): H02H9/02
Inventor 刘平竹
Owner BEIJING JIAOTONG UNIV