DE202016103270U1 - DC circuit breaker with two commutation sections - Google Patents

Abstract

A DC circuit breaker (1) for interrupting a direct current, said DC circuit breaker comprising: a breaker section (10) having a breaker (2); a first commutating section (11a) having a first capacitor (3a) and a first inductive resistor (4a) connected in series; a second commutating section (11b) having a second capacitor (3b) and a second inductive resistor (4b) connected in series; wherein the breaker section (10), the first commutation section (11a) and the second commutation section (11b) are all connected in parallel.

Description

TECHNICAL AREA

The invention relates to a DC (GS) circuit breaker with two Kommutierungsteilabschnitten.

GENERAL PRIOR ART

For interrupting a high voltage DC current, HVDC, it is possible to use a resonant circuit having a capacitor and an inductor in parallel with a breaker. The resonant circuit is triggered by an arc voltage of the interrupter, which superimposes a resonant current to the DC current, whereby a current zero crossing is generated, which leads to arc extinction in the interrupter.

The rated current of the DC circuit breaker depends on the capacitance and inductance of the resonant circuit. In particular, the rated current increases with increased capacitance and reduced inductance.

EP 2 289 085 B1 discloses a device for interrupting DC currents exceeding 2,500 amperes. The device has a resonant circuit connected in parallel with a breaker and a surge arrester connected in parallel with the resonant circuit. The resonant circuit has a series connection of a capacitor and an inductive resistor. The relationship of the capacitance in μF to the inductance in μH of the resonant circuit is ≧ 1.

However, the current interrupt rated power with the prior art design is only about 5,000 A, which is not enough for all applications. One way to achieve increased power interruption rating could be to increase capacity. Increased capacity, however, leads to a significant cost increase, both for the capacitors and for increased physical space requirements. Another way to achieve such nominal power interrupting power could be to reduce the inductance, but the inductance has a minimum value due to geometric constraints.

SUMMARY

It is an object to provide a DC circuit breaker with improved performance.

According to a first aspect, a DC (DC) circuit breaker is provided for interrupting a DC current. The DC circuit breaker includes: a breaker section having a breaker; a first commutation section having a first capacitor and a first inductive resistor connected in series; a second commutating section having a second capacitor and a second inductive resistor connected in series; wherein the breaker section, the first commutation section and the second commutation section are all connected in parallel.

The DC circuit breaker may further include an overvoltage section having an overvoltage protection circuit, and wherein the overvoltage section is connected in parallel with the interrupt section, the first commutation section, and the second commutation section.

The first capacitor and the second capacitor may have substantially equal capacitances.

The first inductive resistor and the second inductive resistor both may be inherently in the structure of the DC circuit breaker.

The first commutation section may be provided on one side of the circuit breaker, in which case the second commutation section is provided on an opposite side of the circuit breaker.

In general, all technical terms used in the claims are to be construed according to their ordinary meaning in the technical field, unless expressly defined otherwise herein. All references to "one, the, the element, device, component, means, step, etc." are to be construed as referring to at least one example of the element, device, component, means, step, etc., as far as not expressly stated otherwise. The steps of any method disclosed herein need not be performed in the precise order disclosed, unless expressly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings; show it:

1 a schematic diagram illustrating an embodiment of a DC circuit breaker.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. However, this invention may be embodied in numerous forms and is not to be construed as limited to the embodiments set forth herein; instead, the embodiments are provided by way of example so that the disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

1 is a schematic diagram showing the structure of a DC circuit breaker 1 for interrupting a direct current between a first point 20 and a second point 21 represents.

A breaker section 10 has a breaker 2 on. Optionally, the breaker section 10 several breakers 2 which are connected in series. The breaker 2 For example, it may be a mechanical switch, which is optionally provided in a gas chamber.

A first commutation section 11a has a first capacitor 3a and an inductive resistor 4a which are connected in series. A second commutation section 11b has a second capacitor 3b and an inductive resistor 4b which are connected in series. The first inductive resistor 4a and the second inductive resistor 4b Both are optionally inherently in the structure of the DC circuit breaker 1 , In other words, the inductive resistors 4a -B only be the result of the self-inductance of a conductor, for the parallel connection of the respective capacitors 3a . 3b with the breaker 2 is used. Each of the capacitors 3a -B may be formed by a capacitor bank to achieve appropriate capacity.

The breaker section 10 , the first commutation section 11a and the second commutation section 11b are all connected in parallel.

Optionally, the DC circuit breaker 1 further an overvoltage subsection 12 on, which has a surge protection circuit 7 having. The overvoltage subsection 12 is with the first breaker section 10 , the first commutation section 11a and the second commutation section 11b connected in parallel. The overvoltage protection circuit 7 may be, for example, a surge arrester or a damper. The overvoltage protection circuit may be implemented using a varistor, a capacitor, an RC (resistor / capacitor) attenuator, an RCD (resistor / capacitor / diode) attenuator, a capacitor, or any combination of the specified attenuator types, such as varistor and RC. The overvoltage protection circuit 7 is configured to start conducting when the voltage across the breaker 2 has reached a certain value when it is opened.

The first capacitor 3a and the second capacitor 3b do not have to be the same. The first capacitor 3a and the second capacitor 3b however, may be provided with substantially equal capacities, whereby the currents through the two Kommutierungsteilabschnitte 11a . 11b are symmetrical.

By the series connection of the capacitor and the inductive resistor in the Kommutierungsteilabschnitten the resulting resonant circuit provides an oscillating current, which is based on a direct current through the breaker 2 for interrupting to zero crossing of the current through the breaker 2 is superimposed. This will make the bow of the breaker 2 cleared and the power can be interrupted when the breaker 2 is opened.

When the electricity is in the breaker 2 is interrupted, the current becomes the Kommutierungsteilabschnitten 11a -B turned and starts the capacitors 3a -B until the voltage is high enough so that the surge arrester begins to conduct at a voltage lower than the rated voltage of the breaker 2 is.

Accordingly, each of the commutation sections has 11a -B has a passive resonant circuit activated by selecting a relationship of capacitance to inductance. A control unit 22 is intended to control the openings of the breaker after the occurrence of any event such as failure, maintenance, etc.

In the prior art, there is only one resonant circuit using a commutation section. The capacitor of the commutation section may be provided on a platform to provide a safe geometric distance to ground when applied to a high voltage level. The inductance of the commutation section is a result of the physical space of a loop resulting from the connections between the breaker and the capacitor.

In embodiments illustrated herein, there are two commutation sections. Thereby, the capacitors can be arranged such that the inductance by minimizing the magnetic energy in the system is significantly reduced. Reductions of approximately 25% are thereby made possible. In one simulation, the inductance was reduced from 12.7 μH to 9.6 μH, a reduction of 24.4%.

The first commutation section 11a may be provided on one side of the breaker, and the second Kommutierungsteilabschnitt 11b is on an opposite side of the breaker 2 intended. In particular, the first capacitor 3a and the second capacitor 3b on both sides of the breaker 2 be provided to thereby reduce the inductance. In addition, the first capacitor 3a and the second capacitor 3b as close as possible to the breaker 2 be provided to provide a low inductance.

The reduced inductance may be used to increase the DC cutoff power rating of the DC circuit breaker and / or to reduce the size and cost of the capacitors for a particular nominal power interruption rating. The concept of the two commutation sections has been tested and verified for currents of 7,000 A.

The invention has been described above mainly with reference to a few embodiments. However, as will be readily apparent to those skilled in the art, other embodiments than those disclosed above are equally possible within the scope of the invention as defined by the appended claims.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2289085 B1 [0004]

Claims (5)

DC circuit breaker ( 1 ) for interrupting a direct current, said direct current circuit breaker comprising: a breaker section (10); 10 ), a breaker ( 2 ) having; a first commutation section ( 11a ), a first capacitor ( 3a ) and a first inductive resistor ( 4a ) connected in series; a second commutation section ( 11b ), which has a second capacitor ( 3b ) and a second inductive resistor ( 4b ) connected in series; the interrupter section ( 10 ), the first commutation subsection ( 11a ) and the second commutation section ( 11b ) are all connected in parallel. DC circuit breaker ( 1 ) according to claim 1, further comprising an overvoltage subsection ( 12 ), which has a surge protection circuit ( 7 ), and wherein the overvoltage subsection ( 12 ) with the breaker section ( 10 ), the first commutation subsection ( 11a ) and the second commutation section ( 11b ) is connected in parallel. DC circuit breaker ( 1 ) according to one of claims 1 or 2, wherein the first capacitor ( 3a ) and the second capacitor ( 3b ) have substantially equal capacities. DC circuit breaker ( 1 ) according to one of the preceding claims, wherein the first inductive resistor ( 4a ) and the second inductive resistor ( 4b ) both inherently in the structure of the DC circuit breaker ( 1 ) are. DC circuit breaker ( 1 ) according to one of the preceding claims, wherein the first commutation section ( 11a ) on one side of the breaker ( 2 ) is provided and the second Kommutierungsteilabschnitt ( 11b ) on an opposite side of the breaker ( 2 ) is provided.

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