CN202772580U - Generator-side voltage regulating system based on reactive power support and used for double-fed wind turbine generator - Google Patents

Abstract

The utility model relates to a generator-side voltage regulating system based on reactive power support and used for a double-fed wind turbine generator. The generator-side voltage regulating system based on reactive power support and used for the double-fed wind turbine generator includes an electric energy quality module measuring generator-terminal voltage in real time; a dead zone hysteresis comparator judging that whether a generator-terminal voltage error e is in an interval of a dead zone or not and arranging a Kth hysteretic link at a threshold value of the dead zone in the absence of the adjustment of the reactive power support; a PI controller calculating reactive power given QPI required by the wind turbine generator for adjusting generator-terminal voltage; a reactive power capacity calculating module calculating the maximum reactive power capacity Qmax under the current active power and determining a reactive power control instruction Qout according to the QPI and the Qmax; and a converter realizing adjustment of the generator-terminal voltage according to the reactive power instruction. The generator-side voltage regulating system based on reactive power support and used for the double-fed wind turbine generator provided by the utility model gives full play to decoupling control characteristics of active power and reactive power of the double-fed wind turbine generator, realizes the dynamic adjustment of voltage of a double-fed wind power plant, improves the quality of a power grid and reduces cost at the same time.

Description

The set end voltage regulating system of double-fed fan motor unit reactive power support

Technical field

The utility model relates to a kind of wind power generation field, particularly relates to a kind of set end voltage regulating system of double-fed fan motor unit reactive power support.

Background technology

Along with wind power generation constantly develops, the wind energy turbine set installed capacity is risen year by year in recent years, and the shared ratio of wind power generation is increasing, becomes gradually a kind of conventional energy resource.Yet the randomness of wind energy can affect to power grid quality so that power and the voltage of the output of wind-powered electricity generation unit have certain stochastic volatility.Along with the expansion of China's separate unit wind turbine pool-size and the rising of total installation of generating capacity proportion in national grid, when the wind-powered electricity generation unit is incorporated into the power networks the coverage of electrical network is also enlarged gradually and influence degree is also being deepened.Therefore State Grid Corporation of China has proposed higher requirement to the serviceability of wind-powered electricity generation unit, be that wind farm grid-connected point voltage is in 0.9-1.1 times of rated voltage (containing boundary value) scope the time, the unit that is incorporated into the power networks should be able to normally move continuously in, and has certain overvoltage capabilities (rated voltage 1.3 times).Yet inner all electric components of wind-powered electricity generation unit, its operating voltage range that can bear is generally 0.9-1.1 times of rated voltage.

For this problem, two kinds of solutions are arranged at present: a kind of is the operating voltage level that improves inner all electric components of wind-powered electricity generation unit, it is replaced by the electric equipment that can bear 1.3 times of rated voltages, this will expend a large amount of manpower and materials, and be a kind of passive method that meets the demands, can't adapt to following possible new variation; The 2nd, throw in the regulatory function that the reactive-load compensation equipments such as more SVC and SVG are realized voltages, by reactive power support set end voltage is adjusted in the 0.9-1.1 times of range of nominal tension, the cost but this can increase input, and be difficult to realize the dynamic adjustments of set end voltage.Therefore, for the double-fed fan motor field, actively bring into play the reactive power capability of wind-powered electricity generation unit, research has great importance based on the dynamic regulating method of the set end voltage of reactive power support.

The utility model content

The technical problems to be solved in the utility model provides a kind of set end voltage regulating system of double-fed fan motor unit reactive power support, make its reactive power support ability of utilizing the double-fed fan motor unit realize the closed-loop adjustment of set end voltage, to guarantee when set end voltage fluctuates, the wind-powered electricity generation unit voltage is adjusted within (100 ± 10) % range of nominal tension by reactive power support, so that still can normally move continuously.

For solving the problems of the technologies described above, the set end voltage regulating system of a kind of double-fed fan motor unit of the utility model reactive power support comprises: set end voltage is measured in real time, and produced the quality of power supply module of feedback signal; Judge the set end voltage error e whether in the interval, dead band, when in the interval, dead band, reactive power support is not regulated, and at the threshold value place in dead band K is set _ThThe dead band hysteresis loop comparator of hysteresis link; When e is not in the interval, dead band, calculates the wind-powered electricity generation unit and regulate the required idle given Q of set end voltage _PIThe PI controller; Calculate the maximum reactive capability Q under the current active power _Max, and according to Q _PI, Q _MaxDetermine idle control command Q _OutThe reactive capability computing module; And according to idle instruction, drive the double-fed fan motor unit and send the current transformer that corresponding reactive power is regulated set end voltage.

After adopting such design, the utility model compared with prior art has following beneficial effect:

1, gives full play to the advantage of double-fed fan motor unit reactive power support, realized the closed-loop adjustment of set end voltage;

2, reduce the capacity of the reactive-load compensation equipments such as double-fed fan motor field SVC and SVG, reduced input cost;

3, the idle dynamic that has realized the double-fed fan motor field supports, and is conducive to the raising of power grid quality.

As mentioned above, the utility model has the principle of regulating power to set end voltage according to reactive power, given full play to the decoupling zero control characteristic of double-fed fan motor unit active power and reactive power, by the harvester terminal voltage as system feedback signal, realization is regulated the automated closed-loop of wind-powered electricity generation unit set end voltage, application of the present utility model can effectively realize the dynamic adjustments of voltage of double-fed wind power station, improve the quality of electrical network, reduce simultaneously the capacity of existing idle conditioning equipment SVC and SVG, reduced cost.

Description of drawings

Fig. 1 is the composition frame chart of the set end voltage regulating system of the utility model double-fed fan motor unit reactive power support.

Fig. 2 is the workflow block diagram of the set end voltage regulating system of the utility model double-fed fan motor unit reactive power support.

Embodiment

Below in conjunction with accompanying drawing preferred embodiment of the present utility model is described, should be appreciated that preferred embodiment described herein only is used for description and interpretation the utility model, and be not used in restriction the utility model.

See also shown in Figure 1ly, the set end voltage regulating system of the utility model double-fed fan motor unit reactive power support comprises quality of power supply module, dead band hysteresis loop comparator, PI controller, reactive capability computing module and current transformer and double-fed fan motor unit.

Wherein, quality of power supply module is measured in real time to set end voltage, and produces feedback signal.

The dead band hysteresis loop comparator realizes that reactive power support is not regulated when voltage error e is in the interval, dead band, at the threshold value place in dead band K is set simultaneously _ThThe hysteresis link.

The PI controller is realized the core algorithm of control procedure, when e is not in the interval, dead band, calculates institute's wind-powered electricity generation unit and regulates the required idle given Q of set end voltage _PI

The reactive capability computing module calculates the maximum reactive capability Q under current active power by the computing formula of apparent power _Max, and according to Q _PI, Q _MaxDetermine idle control command Q _Out, to realize meritorious preferential control strategy.

Current transformer is according to idle instruction, and driving double-fed fan motor unit sends corresponding reactive power set end voltage is regulated, thereby realizes the set end voltage closed-loop control.

In system of the present utility model, by real-time measurement set end voltage value, the reference voltage comparison with given obtains voltage deviation.Controller calculates idle instruction according to voltage deviation and PI control algolithm.Current transformer sends corresponding reactive power according to idle order-driven double-fed fan motor unit and regulates set end voltage, realizes that the closed-loop dynamic of set end voltage is regulated.

Please cooperate and consult shown in Figure 2ly, the job step of the set end voltage regulating system of the utility model double-fed fan motor unit reactive power support comprises: system initialization; Measuring machine terminal voltage, and the error of calculation; Error in judgement and is calculated idle given Q whether between the dead band _PICalculate the maximum reactive capability Q of double-fed fan motor unit this moment _MaxAccording to Q _PIAnd Q _MaxDetermine idle control command Q _OutAccording to idle control command Q _Out, drive the double-fed fan motor unit and send corresponding reactive power.

Specifically, the step 1 system initialization comprises: cumulative errors e _SumZero clearing, given reference voltage U _Ref, dead band (δ, δ) is set as required, and with dead band hysteresis COEFFICIENT K _ThBe set to 1.

For example, usually with given reference voltage U _RefBe set to 690V, δ can be set to 10%.

Need to prove: because the voltage of State Grid Corporation of China regulation is in (100 ± 10) % fluctuation range the time, the operation of the necessary continous-stable of wind-powered electricity generation unit, wind-powered electricity generation unit have possessed the ability of stable operation in (100 ± 10) % range of nominal tension when design.Therefore the utility model the deviation of set end voltage closed-loop adjustment can be arranged a dead band (such as be made as ± 10%, the delay component of taking into account system reactive power support, can the dead time is smaller), when deviation is in dead zone range, controller does not need to send and idle electrical network is carried out supporting order, and the wind-powered electricity generation unit just can stable operation.Simultaneously, in order to prevent at error dead band Near Threshold frequent starting and to stop wind-powered electricity generation unit reactive power, can a hysteresis interval be set at Near Threshold.In follow-up control, can pass through the size of regulating error dead band threshold value to regulate the maintenance level of set end voltage, namely the dead band is less, and set end voltage is more close to given reference voltage, and stability is higher; By the size of dead band hysteresis is set, can reduce the start and stop frequency of wind-powered electricity generation unit reactive power capability.

Step 2, measuring machine terminal voltage, and and U _RefRelatively calculate voltage error e.

Step 3, whether error in judgement e is at-δ U _RefK _ThWith δ U _RefK _ThBetween: if-δ U _RefK _Th≤ e≤δ U _RefK _Th, idle given Q then _PIBe zero, simultaneously with cumulative errors e _SumZero clearing, and dead band hysteresis COEFFICIENT K is set _Th Be 1; If e＜-δ U _RefK _Th, then with capacitive reactive power set end voltage is regulated e _Sum=e _Sum+ e, and calculate idle given Q according to the PI algorithm _PI, simultaneously, set K _Th=k, (0＜k＜1); If e＞δ U _RefK _Th, then set end voltage is regulated e so that perception is idle _Sum=e _Sum+ e, and calculate idle given Q according to the PI algorithm _PI, simultaneously, set K _Th=k, (0＜k＜1).

Better, PI control algolithm of the present utility model adopts the position model PI control algolithm after the distortion, and calculating formula is:

$u_k=K_p\·e_k+K_i\underset{j=0}{\overset{k}{\mathrm{\Σ}}}{e}_j.$

Because capacitive reactive power and the idle impact property of there are differences on set end voltage of perception, so the PI parameter K of capacitive reactive power _Cp, K _CiWith the idle PI parameter K of perception _Lp, K _LiTwo groups of different control parameters.When with capacitive reactive power set end voltage being regulated, Q _PIComputing formula be Q _PI=K _CpE+K _Cie _SumWhen so that perception is idle set end voltage being regulated, Q _PIComputing formula be Q _PI=K _LpE+K _Lie _Sum

Step 4 is calculated the at this moment maximum reactive capability Q of double-fed fan motor unit _Max

Wherein, Q _MaxComputing formula be the apparent power formula

Wherein, S is the apparent power capacity, and P is the active power of present moment.

Step 5 is judged and is regulated the required reactive capability Q of set end voltage _PIWhether exceed Q _MaxIf: do not exceed, i.e. Q _PIAbsolute value be less than or equal to Q _Max, then send corresponding reactive power Q according to requirement command control double-fed fan motor unit _PI, i.e. idle control command Q _Out=Q _PIIf exceeded the reactive power capacity, then according to maximum Q _MaxControl double-fed fan motor unit sends reactive power, i.e. Q _PI=± Q _Max, capacitive reactive power is for just, and lagging reactive power is for negative.

Step 6 is according to controller result of calculation, with idle control command Q _OutSend to current transformer, current transformer drives the double-fed fan motor unit and sends corresponding reactive power, realizes that the closed-loop dynamic of set end voltage is regulated.

The set end voltage regulating system of the utility model double-fed fan motor unit reactive power support, utilize the decoupling zero control characteristic of double-fed fan motor unit active power and reactive power to make up the set end voltage closed loop, realize the dynamic adjustments of double-fed fan motor unit set end voltage, improved the adaptive capacity of wind-powered electricity generation unit when voltage ripple of power network.

It should be noted that at last: the above only is preferred embodiment of the present utility model, be not limited to the utility model, although with reference to previous embodiment the utility model is had been described in detail, for a person skilled in the art, it still can be made amendment to the technical scheme that aforementioned each embodiment puts down in writing, and perhaps part technical characterictic wherein is equal to replacement.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., all should be included within the protection range of the present utility model.

Claims (1)

1. the set end voltage regulating system of a double-fed fan motor unit reactive power support is characterized in that comprising:

Set end voltage is measured in real time, and produced the quality of power supply module of feedback signal;

Judge the set end voltage error e whether in the interval, dead band, when in the interval, dead band, reactive power support is not regulated, and at the threshold value place in dead band K is set _ThThe dead band hysteresis loop comparator of hysteresis link;

When e is not in the interval, dead band, calculates the wind-powered electricity generation unit and regulate the required idle given Q of set end voltage _PIThe PI controller;

Calculate the maximum reactive capability Q under the current active power _MaxAnd according to Q _PI, Q _MaxDetermine idle control command Q _OutThe reactive capability computing module; And

According to idle instruction, drive the double-fed fan motor unit and send the current transformer that corresponding reactive power is regulated set end voltage.

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