CN109888743A

CN109888743A - A kind of decompression clamping type dc circuit breaker suitable for DC grid

Info

Publication number: CN109888743A
Application number: CN201910149915.1A
Authority: CN
Inventors: 贾秀芳; 李嘉龙; 赵西贝; 许建中; 赵成勇
Original assignee: North China Electric Power University
Current assignee: North China Electric Power University
Priority date: 2019-02-28
Filing date: 2019-02-28
Publication date: 2019-06-14

Abstract

The present invention relates to a kind of decompression clamping type dc circuit breakers suitable for DC grid, belong to multiterminal element, DC grid technical field；The topology can be divided into four branches, and respectively pincers pressure current limliting branch, charging paths, stable state low-loss branch and afterflow is consumed energy branch, need using to devices such as capacitor, disconnecting switch, resistance and inductance.Net side line voltage distribution is reduced to zero, to eliminate DC Line Fault by accessing recharged capacitance, and the effect of the clamp voltage and limitation increase in current generated using its charging in fault loop by the decompression clamping type dc circuit breaker.

Description

A kind of decompression clamping type dc circuit breaker suitable for DC grid

Technical field

The present invention relates to a kind of decompression clamping type dc circuit breakers suitable for DC grid, belong to multiterminal element, direct current Electrical network field.

Background technique

Flexible DC transmission is power transmission technology of new generation, can be used for the neck such as Power System Interconnection and renewable energy access Domain.Multiterminal element and DC grid based on flexible DC transmission are one of the important directions of the following power network development and change.Mesh Preceding is the landmark project of China's direct current transportation in Zhangbei County's engineering built, following DC grid engineering will to more multiterminal, it is bigger Capacity, higher reliability direction develop.In remote DC transmission engineering, overhead line transmission is main transmission mode, Overhead line is exposed to the external world, and failure risk is high；In addition, the development speed of DC Line Fault is exceedingly fast, fault current is big and there is no certainly Right zero crossing, so that the removing of DC Line Fault is more difficult, this proposes very high requirement to DC grid fault clearance strategy. Current implementation method is divided into following several: generating current zero-crossing point based on superimposed oscillation electric current, and then realizes electric current disjunction, lacks Point be off delay it is too long, cut-off current is limited；DC line increases inversion-rectification link, and the exchange side after inversion is handed over Circuit breaker trip electric current is flowed, the disadvantage is that turn-off delay is big, could be turned off until current zero-crossing point, and loss is big, involves great expense； With a large amount of power electronic devices connect, above lightning arrester connected in parallel, electric current flows through the lower branch of impedance in normal work, rise To low-loss effect is dropped, electric current is first transferred to power electronics branch when off, then opens disconnecting switch, then electricity consumption Power electronic device is turned off, and absorbs fault energy with arrester.The disadvantage is that cut-off current is limited, and will first will be electric when turning off Circulation moves on to power electronics branch, also waits for disconnecting switch and fully opens, increases turn-off delay to a certain extent.Part Independent of the fault clearance strategy of dc circuit breaker, such as half full mixed topology, due to biggish number of devices and operation damage Consumption, is difficult to realize preferable economy.The exploitation of dc circuit breaker in the following multiterminal element and DC grid still has very much Problems demand solves, and research is suitable for high voltage, high current occasion, and has good rapidity, the DC Line Fault of economy clear Except strategy have become there is an urgent need to.

Summary of the invention

In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a kind of decompression clamping types suitable for DC grid Dc circuit breaker.

It is an object of the invention to overcome low current high voltage DC breaker capacity, rapidity and less economical disadvantage.

The technical scheme adopted by the invention is that: when operating normally, breaker flows through normal operating current, no The normal operation of influence system；When DC line fault occurs, by the clamp capacitor that charge circuit is pre-charged, limited in clamper It flows back to by access main circuit in road, the high voltage generated using its charging and metering function make line voltage distribution be reduced zero, route On disconnecting switch can disjunction faulty line；The energy of the route storage of failure side can be consumed by afterflow energy consumption circuit Energy.

Compared with prior art, the present invention has the advantage that are as follows:

1, rapidity is high, firstly, this programme after voltage is reduced to zero can disjunction Fast mechanical switch, Quick mechanical opens Failure after opening is closed just to be removed, it is fully erased without waiting for failure, reduce turn-off delay；Further, since capacitor passes through Precharge is crossed, so capacitor has had higher voltage when failure occurs, so Fault Isolation can be more quickly completed Operation, further improves removing speed.

2, at low cost, this programme does not need to carry out a large amount of power electronic devices in series and parallel to realize fault clearance, only The capacitor of low-capacitance is needed to carry out auxiliary operation, the cost of capacitor can be far smaller than the cost of power electronic devices.

3, economical operation, for this programme in steady-state operation, the power electronic devices quantity accessed in circuit is much Less than Traditional DC breaker scheme, so generated turn-on consumption and turn-off power loss are smaller, always in steady-state operation Loss it is also just more low so that the operation of breaker is more economical.

Detailed description of the invention

The following further describes the present invention with reference to the drawings.

Fig. 1 shows a kind of decompression clamping type direct-current breaker topology structural schematic diagram suitable for DC grid, including Pincers pressure current limliting branch, charging paths, stable state low-loss branch and afterflow energy consumption branch；

Fig. 2 shows charging stage schematic diagrames；

Fig. 3 shows pincers pressure current limliting stage schematic diagram；

Fig. 4 shows afterflow energy consumption stage schematic diagram.

Specific embodiment

Below in conjunction with the attached drawing in the embodiment of the present application, technical solutions in the embodiments of the present application carries out clear, complete Site preparation description.

A kind of decompression clamping type direct-current breaker topology structural schematic diagram suitable for DC grid is as shown in Figure 1, include Pincers pressure current limliting branch, charging paths, stable state low-loss branch and afterflow energy consumption branch；

Fig. 2 shows charging stage schematic diagrames, when charging starts, open disconnecting switch UFD2 for derided capacitors Cc, charging Resistance Rc and charging inductance Lc accesses charge circuit, and DC line starts to charge to clamp capacitor C at this time, and DC current Idc points Stream is steady-state current Isteady and charging current Icharge two parts, as shown in Fig. 2 (b).Due to having accessed two poles in circuit Pipe, after the voltage of clamp capacitor C reaches peak, which will not enter concussion process, and electric current will drop to zero, at this time It turns off UFD2 and charging paths is isolated, charging process terminates.

Fig. 3 shows pincers pressure current limliting stage schematic diagram, and t0 moment failure occurs, and fault current Ifault is by converter station through low Loss branch flows to fault point, as shown in Fig. 3 (a).

T1 moment system detection issues instruction locking T1 to failure, and the fault current of low-loss branch road is quickly transferred to In the branch of T2 and current-limiting resistance R composition, and preliminary current limliting is carried out by current-limiting resistance R, as shown in Fig. 3 (b).When flowing through UFD1's When electric current is reduced to 0, UFD1 is turned off.Since disconnecting switch shutdown generally has 2-3ms delay, therefore need that UFD1 is waited to complete switch off, Next step operation can just be carried out.

T2 moment, UFD1 are complete switched off, and are latched T2 at this time clamp capacitor C is accessed fault current circuit, are made it first It further charges on the basis of beginning voltage, utilizes the DC voltage of its backward voltage clamper converter station generated.In the process, Electric current in pincers pressure current limliting branch is declined with biggish speed, therefore also needs to open T3 simultaneously to provide afterflow time for fault current Road.Current on line side Igrid is by pincers pressure branch current Iclamp and afterflow energy consumption electric current Iconsume two parts, such as figure during being somebody's turn to do Shown in 3 (c).

T3 moment, pincers pressure branch current are down to zero, UFD3 are turned off with isolated fault route, which also needs 2- The delay of 3ms.

Fig. 4 shows afterflow energy consumption stage schematic diagram, and t4 moment UFD3 is complete switched off, and is latched T3, by energy consumption capacitor Cc, consumption The energy consumption branch access of energy resistance Rc and energy consumption inductance Lc composition, the process of quickening route energy consumption.

T5 moment, energy consumption are completed, and fault clearance operation is completed.

Finally it should be noted that: described embodiment is only some embodiments of the present application, rather than whole realities Apply example.Based on the embodiment in the application, those of ordinary skill in the art are obtained without making creative work Every other embodiment, shall fall in the protection scope of this application.

Claims

1. a kind of decompression clamping type dc circuit breaker suitable for DC grid, it is characterised in that: including pincers pressure current limliting branch, fill Electric branch, stable state low-loss branch and afterflow consume energy branch, need using to IGBT switch, capacitor, disconnecting switch, resistance and electricity The devices such as sense.

2. a kind of decompression clamping type dc circuit breaker suitable for DC grid according to claim 1, it is characterised in that: The effect of pincers pressure current limliting branch is that capacitor is accessed circuit, to play the role of failure clamper and current limliting；The work of charging paths With being pre-charged to capacitor；The effect of stable state low-loss branch is to flow through steady-state current in stable state；The road of afterflow energy consumption Effect be to provide continuous current circuit after Fault Isolation for the residual current on route, consume energy simultaneously.

3. a kind of decompression clamping type dc circuit breaker suitable for DC grid according to claim 1, it is characterised in that: Charging stage, charge circuit by capacitor and charging resistor, derided capacitors etc. jointly access, line voltage distribution to capacitor charging so that Capacitance voltage can have certain initial voltage before fault clearance operation.

4. a kind of decompression clamping type dc circuit breaker suitable for DC grid according to claim 1, it is characterised in that: Electric current is transferred to pincers pressure current limliting circuit, later again by clamp capacitor by pincers pressure current limliting stage, the first IGBT in disconnection major loop Circuit is accessed, so that the clamp capacitor for having initial voltage limits electric current, while the high voltage after charging can be right Failure DC voltage carries out clamper.

5. a kind of decompression clamping type dc circuit breaker suitable for DC grid according to claim 1, it is characterised in that: It consumes energy the stage in afterflow, since clamper terminates, failure is isolated, and the residual current by failure side line road is needed to disappear at this time Consumption is to remove failure, by providing continuous current circuit for residual current, while utilizing resistance and electricity for afterflow energy consumption circuit access Hold consumption residual current.