Combined direct current circuit breaker and application method thereof

Patent metadata

Field	Value
Publication number	US-10756535-B2
Application number	US-201716067602-A
Country	US
Kind code	B2
Filing date	May 22, 2017
Priority date	Jul 20, 2016
Publication date	Aug 25, 2020
Grant date	Aug 25, 2020

Abstract

A combined direct current circuit breaker includes a transfer branch, an energy absorption branch, at least two primary branches and at least two secondary branches; the transfer branch is connected in parallel with the energy absorption branch; the primary branches are in one-to-one correspondence with the second branches; the primary branches are connected with direct current outgoing lines of a direct current busbar in a high-voltage direct current power transmission system; the secondary branches are connected in series with the transfer branches and then connected in parallel with two ends of the primary branches corresponding to the secondary branches.

First claim

The invention claimed is:

1. A combined direct current circuit breaker, comprising one transfer branch, one energy absorption branch, at least two primary branches and at least two secondary branches,
wherein the transfer branch is connected in parallel with the energy absorption branch;
the primary branches are in one-to-one correspondence with the second branches; the primary branches are connected with direct current outgoing lines of a direct current busbar in a high-voltage direct current power transmission system; and the secondary branches are connected in series with the transfer branch and then connected in parallel with two ends of the primary branches corresponding to the secondary branches,
wherein the at least two secondary branches have a common connection point with the transfer branch.

2. The combined direct current circuit breaker according to claim 1 , wherein
each primary branch comprises at least one quick mechanical switch and at least one power electronic switch connected in series, and is arranged to conduct a load current when the high-voltage direct current power transmission system normally runs;
each secondary branch comprises at least one quick mechanical switch and at least one power electronic switch connected in series, and is arranged to isolate a current and voltage between the direct current outgoing lines;
the transfer branch comprises multiple power electronic switches connected in series, and is arranged to break a failure current when the direct current outgoing line or direct current busbar or direct current converter station connected with any primary branch fails; and
the energy absorption branch comprises a nonlinear resistor or a lightening arrester, and is arranged to break an overvoltage and absorb energy stored by an inductive device in the high-voltage direct current power transmission system when the direct current outgoing line or direct current busbar or direct current converter station connected with any primary branch fails.

3. The combined direct current circuit breaker according to claim 2 , wherein
the mechanical switches comprise serial multi-break mechanical switches or multi-branch parallel mechanical switches; the serial multi-break mechanical switches comprise multiple switches connected in series, and the multi-branch parallel mechanical switches comprise multiple switches connected in parallel; and
the power electronic switches are bidirectional on/off switches.

4. The combined direct current circuit breaker according to claim 2 , wherein
the power electronic switches comprise fully-controlled device reverse-series switches, fully-controlled device reverse-parallel switches, first full-bridge switches, second full-bridge switches and diode bridge type switches;
each fully-controlled device reverse-series switch comprises two fully-controlled power electronic devices reversely connected in series, and each of the fully-controlled power electronic devices is reversely connected in parallel with a diode;
each fully-controlled reverse-parallel switch comprises two fully-controlled power electronic devices reversely connected in parallel;
each first full-bridge switch comprises a full-bridge structure unit, its bridge arm comprises a fully-controlled power electronic device, and its capacitor is connected in parallel with a first resistor;
each second full-bridge switch comprises a full-bridge structure unit, its bridge arm comprises a fully-controlled power electronic device, and its direct current capacitor is connected in series with the diode after being connected in parallel with a second resistor; and
each diode bridge type switch comprises a full-bridge structure unit, its bridge arm comprises a diode, and its direct current capacitor is connected in parallel with the fully-controlled power electronic device.

5. An application method of a combined direct current circuit breaker, comprising switching a working mode of the direct current circuit breaker according to a running state of a high-voltage direct current power transmission system by:
when the high-voltage direct current power transmission system runs normally, switching the direct current circuit breaker into a first working mode;
when the high-voltage direct current power transmission system has a line failure, switching the direct current circuit breaker into a second working mode; and
when the high-voltage direct current power transmission system has a converter station outlet failure, switching the direct current circuit breaker into a third working mode,
wherein the combined direct current circuit breaker comprises one transfer branch, one energy absorption branch, at least two primary branches and at least two secondary branches, wherein the transfer branch is connected in parallel with the energy absorption branch; the primary branches are in one-to-one correspondence with the second branches; the primary branches are connected with direct current outgoing lines of a direct current busbar in a high-voltage direct current power transmission system; and the secondary branches are connected in series with the transfer branch and then connected in parallel with two ends of the primary branches corresponding to the secondary branches.

6. The application method of the combined direct current circuit breaker according to claim 5 , wherein
the switching the direct current circuit breaker into the first working mode comprises:
closing quick mechanical switches of all primary branches and triggering power electronic switches of all the primary branches to be turned on;
closing quick mechanical switches of all secondary branches and latching power electronic switches of all the secondary branches; and
latching power electronic switches of the transfer branch.

7. The application method of the combined direct current circuit breaker according to claim 5 , wherein an initial state of the direct current circuit breaker is that: the quick mechanical switches in all the primary branches are closed, the power electronic switches are turned on, the quick mechanical switches in all the secondary branches are closed, the power electronic switches are latched, and the power electronic switches in the transfer branch are latched;
the switching the direct current circuit breaker into the second working mode comprises:
latching the power electronic switch of the primary branch connected with a failure line, triggering the power electronic switch of the secondary branch corresponding to the primary branch to be turned on, and triggering the power electronic switches of the transfer branch to be turned on;
after a current flows through the primary branch connected with the failure line crosses zero, breaking the quick mechanical switch of the primary branch, and breaking the quick mechanical switch of the secondary branch not corresponding to the primary branch; and
after breaking opening ranges of the quick mechanical switches of the primary branch and the secondary branch withstand a transient breaking voltage, latching the power electronic switches of the transfer branch, transferring a failure current of the failure line to an energy absorption circuit, and when the failure current in the energy absorption circuit crosses zero, recovering the high-voltage direct current power transmission system to run normally.

8. The application method of the combined direct current circuit breaker according to claim 7 , further comprising: after recovering the high-voltage direct current power transmission system to run normally,
controlling the direct current circuit breaker to isolate the failure line, comprising: breaking the quick mechanical switch of the secondary branch corresponding to the primary branch connected with the failure l

Assignees

• Global Energy Interconnection Res Inst Co Ltd
• State Grid Corp China
• Global Energy Interconnection Res Inst Co Ltd

Inventors

• Tang Guangfu
• He Zhiyuan
• Zhou Wandi
• Wei Xiaoguang
• Zhang Sheng
• Zhao Yan
• Luo Xiang
• Li Pengzhi

Classifications

• Y02E60/60

  Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD] · CPC title

• H01H33/596 Primary

  for interrupting DC · CPC title

• H03K17/168

  in composite switches · CPC title

• H02H3/087

  for DC applications · CPC title

• H03K2217/0009

  AC switches, i.e. delivering AC power to a load · CPC title