CN205335866U

CN205335866U - Control system that is incorporated into power networks under wind power system trouble condition

Info

Publication number: CN205335866U
Application number: CN201620070345.9U
Authority: CN
Inventors: 徐广令; 郑雪钦
Original assignee: Xiamen University of Technology
Current assignee: Xiamen University of Technology
Priority date: 2016-01-25
Filing date: 2016-01-25
Publication date: 2016-06-22
Anticipated expiration: 2026-01-25

Abstract

The utility model discloses a control system that is incorporated into power networks under wind power system trouble condition, including wind energy conversion system, gearbox, aerogenerator, crowbar protection circuit, transformer, static reactive compensation device, fuzzy PID controller and electric wire netting, wherein, aerogenerator's input is connected to the output of wind energy conversion system via the gearbox, aerogenerator adopts brushless double -fed generator, transformer adoption 575V25kV step up transformer, aerogenerator passes through 575V's generating line feeder and connects the transformer, by parallelly connected with the electric wire netting again behind the transformer change voltage, static reactive compensation device is connected to fuzzy PID controller, static reactive compensation device connects in parallel on the 25kV generating line, the cross -over connection of crowbar protection circuit is between aerogenerator's rotor side and electric wire netting side. This kind of control system can the accuracy adjust idle change fast when the electric wire netting breaks down, make entire system steadily spend transient, firm energy quality.

Description

A kind of grid-connection control system under wind power system failure condition

Technical field

This utility model belongs to control field, particularly to a kind of wind power system grid-connection control system in case of a fault。

Background technology

Along with the scarcity day by day of conventional energy resource, environmental problem has caused the attention of countries in the world；Along with tradition electrical network problem in the feature of environmental protection etc. is day by day serious, obtain development and utilization widely with the new forms of energy that wind-power electricity generation is representative, but interconnection technology is the obstacle hindering its development further。Owing to wind-power electricity generation itself has unstability, wind generator system can be impacted again when the grid collapses, so that line voltage, frequency, the key parameter such as idle are adversely affected, therefore adopt and in wind power-generating grid-connected system, add suitable control algolithm will become an effective solution route。

At present, the electromotor of wind power-generating grid-connected system adopts influence generator, double-fed asynchronous generator and synchronous generator mostly。When the wind generator system of employing influence generator is grid-connected, influence generator can consume idle, and idle uncontrollable, capacitors count in parallel will carry out classification adjustment line voltage；When the wind generator system of employing double-fed asynchronous generator is grid-connected, utilize the reactive power of the Frequency Converter Control grid side being connected with double-fed asynchronous generator rotor, power factor is adjustable close to 1, but owing to double-fed asynchronous generator is equipped with the device such as carbon brush, slip ring so that it is reliability is not high；Adopt the wind power-generating grid-connected system of synchronous generator, the exciting current realization net side reactive power that can pass through to control synchronous generator is controlled, but it is constant to need wind-driven generator to have accurate speed adjusting gear to maintain synchronous rotational speed when ensureing wind speed change, and the frequency inverter capacity concatenated with synchronous generator stator is bigger。

In the system having wind power generating set to be connected to the grid, electric network fault will have a strong impact on the output voltage of wind power system, and produce very big negative-sequence current。Grid voltage sags can cause the instability of transmission line of electricity voltage, and the fluctuation of two times of mains frequencies can occur reactive power simultaneously, and the performance of wind power system and the safe operation of power system are all worked the mischief by this, even result in out of service。Under current unbalanced grid faults, the guard method of wind power system mainly has Crowbar rotor protection circuit, negative sequence voltage feedforward asymmetric control strategy, electric current positive-sequence component Tracking Control Strategy, D-STATCOM reactive-load compensation etc.。

Utility model content

The purpose of this utility model, is in that to provide the grid-connection control system under a kind of wind power system failure condition, and it can accurately and quickly adjust idle change when grid collapses, makes whole system steadily spend transient process, it is ensured that the quality of power supply。

In order to reach above-mentioned purpose, solution of the present utility model is:

A kind of intelligent wind power system fault control system; circuit, transformator, static passive compensation device, fuzzy controller and electrical network is protected including wind energy conversion system, change speed gear box, wind-driven generator, Crowbar; wherein, the outfan of wind energy conversion system connects the input of wind-driven generator via change speed gear box；Wind-driven generator adopts brushless double feed generator, and transformator adopts 575V/25kV booster transformer, the described wind-driven generator bus feeder line connection transformer by 575V, transformator in parallel with electrical network again after changing voltage；Described fuzzy controller connects static passive compensation device, and described static passive compensation device is connected in parallel on 25kV bus；Described Crowbar protects circuit to be connected across between the rotor-side of wind-driven generator and grid side。

Above-mentioned static passive compensation device adopts voltage-type bridge circuit。

Above-mentioned voltage-type bridge circuit includes 3 branch roads parallel with one another, each branch road all comprises two full-controlled device of series aiding connection, and each equal inverse parallel of full-controlled device has diode, using the midpoint of each bar branch road as outfan, connect respectively through inductance is corresponding with ABC three-phase bus。

Above-mentioned full-controlled device adopts IGBT。

After adopting such scheme, this utility model has the following characteristics that

(1) wind-driven generator in this utility model adopts brushless double feed generator, compares double-fed asynchronous generator and can cancel carbon brush and slip ring, and reduction is worn and torn, noise is low；Compare synchronous generator again can variable-speed operation, decrease speed-adjusting mechanism device, simple in construction；Comparing influence generator, it is adjustable and without shnt capacitor pressure regulation that it is idle；

(2) static passive compensation device in this utility model adopts IGBT switching device, and response speed is very fast, and dynamic property is good, static properties is high, can improve low voltage crossing (LVRT) ability of wind power system。

Accompanying drawing explanation

Fig. 1 is integrated stand composition of the present utility model；

Fig. 2 is the theory diagram that this utility model adopts fuzzy control；

Fig. 3 is the model schematic that this utility model adopts fuzzy control；

Fig. 4 is the voltage-type bridge circuit basic block diagram of static passive compensation device in this utility model。

Detailed description of the invention

Below with reference to accompanying drawing, the technical solution of the utility model and beneficial effect are described in detail。

As shown in Figure 1; this utility model provides a kind of intelligent wind power system fault control system; protect circuit 4, transformator 5, static passive compensation device 6, fuzzy controller 7 and electrical network 8 including wind energy conversion system 1, change speed gear box 2, wind-driven generator 3, Crowbar, introduce separately below。

The outfan of wind energy conversion system 1 connects the input of wind-driven generator 3 via change speed gear box 2, provides power for wind-driven generator 3。

Wind-driven generator 3 adopts brushless double feed generator, compares double-fed asynchronous generator and can cancel carbon brush and slip ring, reduces abrasion, and noise is low；Compare synchronous generator again can variable-speed operation, decrease speed-adjusting mechanism device, simple in construction；Comparing influence generator, it is adjustable and without shnt capacitor pressure regulation that it is idle。

Described transformator 5 adopts 575V/25kV booster transformer, described wind-driven generator 3 to pass through the bus feeder line connection transformer 5 of 575V, transformator 5 in parallel with electrical network 8 again after changing voltage。

Described static passive compensation device 6 is connected in parallel on 25kV bus, coordinate shown in Fig. 4, it it is the basic block diagram of voltage-type bridge circuit, include 3 branch roads parallel with one another, connecting by inductance is corresponding with ABC three-phase bus respectively, each branch road all comprises two full-controlled device (can adopt IGBT) of series aiding connection, and the equal inverse parallel of each full-controlled device has diode, using the midpoint of each bar branch road as outfan, connect inductance。During normal operation, by the break-make of full-controlled device, circuit is accessed electrical network, by changer, DC voltage is converted to alternating voltage, regulate idle change；When line voltage is more than the voltage at D-STATCOM place, D-STATCOM absorbs the reactive power of perception from electrical network, is in rectification state；Otherwise, when line voltage is less than D-STATCOM end place's voltage, D-STATCOM absorbs capacitive reactive power from electrical network, is in inverter mode。The reactive power that static passive compensation device absorbs from system can calculate with formula, in formula, for nonlinear resistance, and；For D-STATCOM absorb total reactive power, for delayed angle；When D-STATCOM absorbs lagging reactive power, time,；Otherwise when D-STATCOM absorbs capacitive reactive power, time,。Therefore the amount of D-STATCOM absorbing reactive power can be controlled by adjusted size of mode。

Described fuzzy controller 7 connects static passive compensation device 6, by adding PID FUZZY ALGORITHMS FOR CONTROL in reactive-load compensation D-STATCOM, when the electrical network of wind power system is short-circuited or during earth fault, can accurately and quickly adjust idle change, whole system quick and stable is made to spend transient process, it is ensured that the quality of power supply。

Described Crowbar protects circuit 4 to be then connected across between rotor-side and the grid side of wind-driven generator 3; and add exclusive circuit in the Crowbar double; two pwm converters protected in circuit; when the electrical network of this wind power system is short-circuited or during earth fault, it is possible to cut off stator loop and then protection wind-driven generator。

As shown in Figures 2 and 3, when this utility model realizes controlling, the feature that when utilizing grid collapses, reactive power fluctuation is relatively larger, Fuzzy PID is used in the outer shroud controlling unit of reactive-load compensation D-STATCOM, by regulating electric power system alternating current side voltage, by the variable gathered after a ratio and differentiation element process, again its departure e and deviation variation rate Δ e is carried out Fuzzy processing as input variable, and carry out computing by the fuzzy rule set up, thus draw fuzzy after output variable, this variable and pid parameter are compared, carry out the size of online its pid parameter of real-time monitoring, according to change in voltage, absorb or send reactive current, reach dynamic compensation effect, the demand of static passive compensation device Reactive-power control can be met better, ensure the quality of power supply of whole electrical network, the control accuracy making whole system is high, fast response time, dynamic property is good, steady-state behaviour is high, it is greatly improved low voltage crossing (LVRT) ability of wind power system。

Above example is only explanation technological thought of the present utility model; protection domain of the present utility model can not be limited with this; every according to the technological thought that the utility model proposes, any change done on technical scheme basis, each fall within this utility model protection domain。

Claims

1. the grid-connection control system under a wind power system failure condition; it is characterized in that: include wind energy conversion system, change speed gear box, wind-driven generator, Crowbar protection circuit, transformator, static passive compensation device, fuzzy controller and electrical network; wherein, the outfan of wind energy conversion system connects the input of wind-driven generator via change speed gear box；Wind-driven generator adopts brushless double feed generator, and transformator adopts 575V/25kV booster transformer, the described wind-driven generator bus feeder line connection transformer by 575V, transformator in parallel with electrical network again after changing voltage；Described fuzzy controller connects static passive compensation device, and described static passive compensation device is connected in parallel on 25kV bus；Described Crowbar protects circuit to be connected across between the rotor-side of wind-driven generator and grid side。

2. the grid-connection control system under a kind of wind power system failure condition as claimed in claim 1, it is characterised in that: described static passive compensation device adopts voltage-type bridge circuit。

3. the grid-connection control system under a kind of wind power system failure condition as claimed in claim 2, it is characterized in that: described voltage-type bridge circuit includes 3 branch roads parallel with one another, each branch road all comprises two full-controlled device of series aiding connection, and each equal inverse parallel of full-controlled device has diode, using the midpoint of each bar branch road as outfan, connect respectively through inductance is corresponding with ABC three-phase bus。

4. the grid-connection control system under a kind of wind power system failure condition as claimed in claim 3, it is characterised in that: described full-controlled device adopts IGBT。