CN103986186A - Wind, solar and water complementary-type micro grid black start control method - Google Patents

Abstract

The invention relates to a wind, solar and water complementary-type micro grid black start control method and belongs to the technical field of optimal control of electric power system micro grids. The method includes the steps that micro grid basic data are read in; distributed power supplies meeting the black start conditions serve as black start power supply alternative units; the black start power supply alternative units are sorted according to power, and the units are sequentially selected as the black start units one by one; according to whether the distributed power supplies are black start power supplies or not and whether the distributed power supplies participate in isolated grid frequency control or not, control strategies or controller parameters are selected, and alternative micro grid black start schemes are obtained; the obtained micro grid black start schemes are subjected to simulation calculation, whether voltages of all nodes of a micro grid and the frequency of the micro grid meet the constraint conditions about stability, a safety threshold and the like is judged when the isolated grid runs in the black start process according to the alternative schemes, the alternative schemes meeting the constraint conditions serve as feasible schemes, and an optimal scheme is selected from the feasible schemes. Due to the method, it is guaranteed that the wind, solar and water complementary-type micro power grid has high reliability and economical efficiency.

Description

The micro-Power Grid Black of a kind of honourable water complementary type starts control method

Technical field

The invention belongs to the micro-network optimization control technology of electric power system field, particularly a kind of black startup optimal control method of the micro-electrical network that contains wind-powered electricity generation, photovoltaic, small power station.

Background technology

Black startup refers to that electrical network, after full cut-off accident, does not rely on external power source, is driven the unit of non self starting by the unit in system with self-startup ability, and expansion system is gradually recovered scope, finally realizes the recovery of whole system.

Microgrid is after large electrical network generation full cut-off accident or lonely network operation itself and generation full cut-off accident, and safety, black startup rapidly have important practical significance to ensureing critical load power supply.The black startup control of microgrid need to be gained merit to the new forms of energy such as small power station and wind, light, idle control microgrid is carried out to Load Regulation, realize the self adaptation of microgrid to black startup preparation, rack recovery and load restoration process voltage, frequency, avoid the convalescent overvoltage problem of self-excitation problem, rack of black initial start stage and the frequency fluctuation problem of load restoration phase.Because distributed power source is as the intermittence of wind-powered electricity generation, photovoltaic and small power station, randomness feature, how to coordinate exerting oneself or adopting the mode of energy storage of the group of small power station, new forms of energy, ensureing on the basis of microgrid safe operation, meeting the required response speed of black startup, response capacity, is the key of black startup success.

More to starting research containing micro-Power Grid Black of wind, photovoltaic, energy storage equipment at present, region small power station/wind, the micro-Power Grid Black of light new forms of energy are started, especially during to black start-up course and the rear lonely network operation of black startup success, all kinds of power supply real power control devices are coordinated to control, and lonely net FREQUENCY CONTROL Study on Problems is less.

Summary of the invention

The object of the invention is the weak point for overcoming prior art, propose the micro-Power Grid Black of honourable water complementary type and start control method, this method can be given full play to the benefit of distribution type renewable energy generating, guarantees that the micro-electrical network of honourable water complementary type has higher reliability and economy.

Technical scheme of the present invention is, on the basis of the wind turbine generator of setting up, photovoltaic, miniature water hydroelectric station dynamic model, research is meeting microgrid black-start scheme and microgrid control strategy best under micro-line voltage, frequency requirement condition, make whole micro-Power Grid Black start-up course under the premise that security is guaranteed, as early as possible, much more as far as possible to recover load.

The micro-Power Grid Black of one scene water complementary type that the present invention proposes starts control method, it is characterized in that, the method comprises the following steps:

(1) read in micro-electrical network basic data, comprise micro-electric network model, microgrid on off state, wind speed, solar irradiation intensity data, the each group of small power station hydrologic regime data, each load bus load prediction data;

(2) using the distributed power source that meets black entry condition as the alternative unit of black startup power supply, otherwise as being activated the alternative unit of power supply;

(3) by the alternative unit of black startup power supply by watt level sequence, get successively wherein a unit as black startup unit; In micro-electrical network, other distributed power sources are as being activated unit, and each distributed power source, according to whether being black startup power supply, whether participating in lonely net FREQUENCY CONTROL selection control strategy and controller parameter, obtains alternative micro-Black-start Schemes of Electric Power Grid;

(4) one by one the alternative micro-Black-start Schemes of Electric Power Grid obtaining in step (3) is carried out to simulation calculation, while judging the black start-up course of alternative and lonely network operation, the constraintss such as whether each node voltage of micro-electrical network and micro-mains frequency meet is stablized, safety limit, meet constraints, as feasible scheme, and choose the best alternatives in feasible program.

The micro-network optimization progress control method of honourable water complementary type that the present invention proposes, its advantage is as follows:

1, black start-up course is utilized regulating power and the generating capacity of small power station, and energy storage device, photovoltaic form complementation.

2, be optimized micro-mains frequency control needs when adapting to black start-up course, lonely network operation for micro-electrical network photovoltaic/energy storage equipment inverter and small power station's set speed adjustment system control strategy and parameter.

3, under taking into account system safe operation restrictive condition, consider multiple black startup strategy, improve flexibility and the adaptability of black-start scheme.

Brief description of the drawings

Fig. 1 is the micro-network optimization progress control method of the honourable water complementary type method flow diagram that the present invention proposes.

Fig. 2 is combining inverter control block diagram in the present invention.

Embodiment

The micro-Power Grid Black of one scene water complementary type that the present invention proposes starts control method by reference to the accompanying drawings and embodiment is described in detail as follows.

The micro-Power Grid Black of the honourable water complementary type of one of the present invention starts control method flow process as shown in Figure 1, comprises the following steps:

(1) read in micro-electrical network basic data, comprise micro-electric network model, microgrid on off state, wind speed, solar irradiation intensity data, the each group of small power station hydrologic regime data, each load bus load prediction data;

(2) using the distributed power source that meets black entry condition as the alternative unit of black startup power supply, otherwise as being activated the alternative unit of power supply;

(3) by the alternative unit of black startup power supply by watt level sequence (small power station's unit, photovoltaic plant are got current stablizing and activity of force, and energy storage equipment is got and ensured stable exerting oneself in 1 hour), get successively wherein a unit as black startup unit; In micro-electrical network, other distributed power sources are as being activated unit, and each distributed power source, according to whether being black startup power supply, whether participating in lonely net FREQUENCY CONTROL selection control strategy and controller parameter, obtains alternative micro-Black-start Schemes of Electric Power Grid;

(4) one by one the alternative micro-Black-start Schemes of Electric Power Grid obtaining in step (3) is carried out to simulation calculation, while judging the black start-up course of alternative and lonely network operation, the constraintss such as whether each node voltage of micro-electrical network and micro-mains frequency meet is stablized, safety limit, meet constraints, as feasible scheme, and in feasible program, choose the best alternatives (in black start-up course, microgrid gross generation maximum).

Above steps embodiment is described as follows:

Step (2) is using the distributed power source that meets black entry condition as the alternative unit of black startup power supply, otherwise conduct is activated the alternative unit of power supply; Specifically comprise:

(2-1) the black entry condition that water wheels unit meets as the alternative unit of black startup power supply is: station service electrical system is working properly; Possesses normal condition for subsequent use (being that unit is at stand-by state); The each portion of unit bearing oil level, oily qualified; Speed regulator forced oil device oil pressure, oil level are in normal range (NR); Machine set outlet switch DC control power supply is normal; The corresponding HV Auxiliary Transformer of unit and on-load switch are normal; Unit and common part control are normal, signal DC power supply is normal; The defect that unit starts without impact;

(2-2) the black entry condition that energy storage equipment/photovoltaic plant meets as the alternative unit of black startup power supply is:

The inverter of energy storage equipment/photovoltaic electric station grid connection possesses islet operation pattern, and anti-isolated island measuring ability exits, and power station entirety meets the code compressor start up condition that puts into operation;

(2-3) the black entry condition that wind-powered electricity generation unit meets as the alternative unit of black startup power supply is:

Wind energy turbine set emergency power supply (as diesel generating set) can meet blower fan auxiliary system power reguirements; Power phase is correct, three-phase voltage balance; Tuning system is in normal condition, anemobiagraph and the wind vane state in normal operation; The oil pressure of the hydraulic means of braking and control system and oil level are in prescribed limit; Gear box oil level and oil temperature are in normal range (NR); Every protective device is all in the correct position of dropping into, and protection definite value all conforms to the value that approval is set; Control power supply in on-position; Control Computer display in normal operating condition; Manually boot on front impeller without the phenomenon of freezing; In cold and humid area, it is qualified that Long-time Shut-down and the wind-powered electricity generation unit newly putting into operation insulate before putting into operation; Through the wind-powered electricity generation unit of maintenance before startup, promising maintenance and the various safety measures set up are removed.

(2-4) black startup Power Selection

Do not having in external electrical network support situation, the self-startup ability of black startup power supply is the key that system completes black startup smoothly.Conventional electric power system is used hydraulic generator unit or large-scale gas turbine group as black startup power supply.By analogy, can draw the principle (power station operations staff can according to the operating standard of this station judge) of micro-grid system on black startup power supply is selected:

A) there is energy-storage units: (because the generating capacity of the regenerative resource such as photovoltaic, wind-powered electricity generation fluctuates obviously in the time that natural conditions change, be difficult to maintain lonely net frequency constant,) energy storage equipment of the first-selected Non-intermittent problem of the black startup power supply of micro-grid system, (source as micro-in batteries to store energy, the micro-source of flywheel energy storage etc.,) this also has round-the-clock startup ability in source slightly, not affected by the extraneous factors such as weather.

B) there is voltage regulation and frequency modulation ability: (for ensureing that micro-grid system is in the voltage under net state and frequency stabilization,) black startup power supply is in having voltage source output characteristic, also there is pressure regulation and frequency modulation function, can ensure the excitatory loss of distribution transformer and micro-grid system ac bus no-load loss, and short-time rating can bear other non-black startup power initiations time impacts.

C) there is enough reserve capacitys: black startup power supply self generating capacity enough, in region, other provides startup power supply without black start-up ability power supply, recovers other generator, and can power to critical load.

(2-5) non-black startup power supply startup sequence

Micro-grid system adopts build down strategy, and each micro-source starts and is incorporated in microgrid one by one under Light Condition, to avoid the also net operation of two isolated microgrids.For reducing voltage and the frequency fluctuation in the black start-up course of microgrid, the boot sequence of non-black startup power supply is: micro-grid system first starts and has the micro-source of the voltage-source type of voltage regulation and frequency modulation ability when unloaded, more progressively starts the micro-source of current source type without frequency modulation and voltage modulation ability.

In step (3), control strategy comprises:

(3-1) combining inverter control mode

Wind-powered electricity generation, photovoltaic and energy storage equipment are incorporated to AC synchronous electrical network by combining inverter, and inverter control pattern can be divided three classes:

1) inverter PQ control model, for double-fed blower fan, under grid-connected state, now the power stage of inverter is followed wind-force/light conditions, to reach the maximum object of meritorious output;

2) inverter V/f control model, now micro-source is as the frequency modulation/voltage controller power source in orphan's net, and the voltage/frequency that maintains lonely net is stable;

3) the Pf/VQ control model of inverter band droop characteristic, now micro-source can have the regulating characteristics of normal power supplies, meritorious output is with frequency change, idle output changes with voltage magnitude, there is well positive regulating characteristics, be very beneficial for the power division between each micro-power supply in lonely net situation, and without communication.

(a) PQ controls, and inverter control flow process as shown in Figure 2.

According to the controlled device current-voltage correlation of Fig. 2:

$v_{\mathrm{gk}}\left(t\right)=v_{\mathrm{ik}}\left(t\right)-[R_t{i}_{\mathrm{gk}}+L_t\frac{{\mathrm{di}}_{\mathrm{gk}}\left(t\right)}{\mathrm{dt}}]k=a,b,c---\left(1\right)$

Formula (1) is carried out to Park conversion, obtains:

$\left\{\begin{array}{c}{v}_{\mathrm{gd}}\left(t\right)=v_{\mathrm{id}}\left(t\right)-[R_t{i}_{\mathrm{gd}}\left(t\right)+L_t\frac{{\mathrm{di}}_{\mathrm{gd}}\left(t\right)}{\mathrm{dt}}-{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gq}}\left(t\right)]\\ v_{\mathrm{gq}}\left(t\right)=v_{\mathrm{iq}}\left(t\right)-[R_t{i}_{\mathrm{gq}}\left(t\right)+L_t\frac{{\mathrm{di}}_{\mathrm{gq}}\left(t\right)}{\mathrm{dt}}+{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gd}}\left(t\right)]\end{array}\right.---\left(2\right)$

ω _nfor system frequency.

V _gd, V _gqmicro-source site d, q shaft voltage; V _id, V _iqinverter output d, q shaft voltage;

I _gd, i _gqmicro-source site d, q shaft current;

Be made as line voltage with reference to axle, have v _gq(t)=0, thus inverter power output is: P _mt=v _gdi _gd; Q _mt=-v _gdi _gq, d, q shaft current is:

$\begin{array}{c}{i}_{\mathrm{gd},\mathrm{ref}}=p_{\mathrm{mt},\mathrm{ref}}/v_{\mathrm{gd}}\\ i_{\mathrm{gq},\mathrm{ref}}=-Q_{\mathrm{mt},\mathrm{ref}}/v_{\mathrm{gd}}\end{array}---\left(3\right)$

Definition:

$\left\{\begin{array}{c}{v}_{\mathrm{id}}^{\′}\left(s\right)=v_{\mathrm{id}}-v_{\mathrm{gd}}+{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gq}}\\ v_{\mathrm{id}}^{\′}\left(s\right)=v_{\mathrm{iq}}-{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gq}}\end{array}\right.---\left(4\right)$

The PQ control strategy of system can be expressed as:

$\left\{\begin{array}{c}{v}_{\mathrm{id}}^{\′}=R_t-i_{\mathrm{gd}}+L_t\frac{{\mathrm{di}}_{\mathrm{gd}}}{\mathrm{dt}}\\ v_{\mathrm{id}}^{\′}=R_t{i}_{\mathrm{gq}}+L_t\frac{{\mathrm{di}}_{\mathrm{gq}}}{\mathrm{dt}}\end{array}\right.---\left(5\right)$

The reference voltage of PWM pulse-width modulation is:

$\left\{\begin{array}{c}{v}_{\mathrm{id},\mathrm{ref}}=v_{\mathrm{id},\mathrm{ref}}^{\′}+v_{\mathrm{gd}}-{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gq}}\\ v_{\mathrm{iq},\mathrm{ref}}=v_{\mathrm{id},\mathrm{ref}}^{\′}+{\mathrm{\ω}}_n{L}_t{i}_{\mathrm{gq}}\end{array}\right.---\left(6\right)$

(b) v/f controls

For islet operation pattern, now output voltage amplitude is made as definite value, and control method is for to be decomposed into d by voltage vector, q axle component, and the deviation of comparison they and set point, is 0 by PI controlling unit by Deviation Control respectively.Frequency signal is produced by DC-to-AC converter itself.

(c) Pf/VQ with droop characteristic controls

Control mode is substantially the same with PQ, controls reference current, the given Pset of magnitude of voltage, Qset value and counts system frequency and standard frequency deviation, output voltage and given voltage deviation for calculating.

Each node voltage and micro-mains frequency of the micro-electrical network of step (4) meets mains frequency, voltage stabilization specifically comprises:

(4-1) voltage stabilization requirement

Generally speaking,, in the time that generator moves in large net, the automatic adjusting excitation system (AVR) of each generator is by adjust the exciting current of its output according to the required reactive power of system, to meet the variation demand of electric network reactive-load.Load or burden without work electric current is the main cause that causes generator voltage to decline; In the time that exciting current is constant, the terminal voltage of generator reduces the increase with reactive current; Therefore, in the time of lonely network operation, the requirement to voltage stabilization of the requirement according to load side to the quality of power supply and station service electrical system, the terminal voltage of generator should remain unchanged substantially.This just requires generating set in the time of lonely network operation, and the automatism voltage control function of the system that should put into excitation AVR makes the exciting current of generator regulate with the variation of System Reactive Power electric current, thereby keeps the relatively stable of generator voltage.

Should be noted that: when unit operation is in the time that orphan nets, the variation of electric network reactive-load electric current must be less than the adjustable range of generator excited system AVR, otherwise line voltage cannot maintain, and may cause tripping operation or the damage of generator.

(4-2) the lonely network operation frequency stabilization of micro-electrical network requirement

For the non-frequency modulation unit operating in large electrical network, generally adopt frequency modulation frequency modulation mode, change after power given value P, maintain to reach the object that system frequency is stable by the regulating characteristics of speed regulator.Generator operation, in the time that orphan nets, generally needs to adopt constant frequency control mode, regulates according to frequency deviation f; In the time of Δ f=0, regulate and finish, namely adopt so-called primary frequency modulation mode.Because lonely network capacity amount is less, the kinetic energy that wherein rotary inertia stores is less, therefore, electrical network requires the governing system of main force's unit to have higher sensitivity, less dead-band and dynamic response faster conventionally, to ensure in the situation that customer charge changes, system frequency modulation unit can keep the stable of mains frequency automatically.Frequency, the voltage control function of the electrical network of isolated operation are mainly born by the main force's generating set in net.In the time of lonely network operation, need to carry out analytical calculation to trend, the stability etc. of whole lonely net, formulate perfect lonely network operation prediction scheme, implement United Dispatching, each node cooperates, in the time that stable condition meets, could successfully carry out lonely net firing test, and realize the stable operation of lonely net; For the unit in the lonely net of operation, its speed governing, excitation, control, protection system all should meet the requirement of lonely network operation.

Claims (4)

1. the micro-Power Grid Black of honourable water complementary type starts a control method, it is characterized in that, the method comprises the following steps:

(1) read in micro-electrical network basic data, comprise micro-electric network model, microgrid on off state, wind speed, solar irradiation intensity data, the each group of small power station hydrologic regime data, each load bus load prediction data;

(2) using the distributed power source that meets black entry condition as the alternative unit of black startup power supply, otherwise as being activated the alternative unit of power supply;

(3) by the alternative unit of black startup power supply by watt level sequence, get successively wherein a unit as black startup unit; In micro-electrical network, other distributed power sources are as being activated unit, and each distributed power source, according to whether being black startup power supply, whether participating in lonely net FREQUENCY CONTROL selection control strategy and controller parameter, obtains alternative micro-Black-start Schemes of Electric Power Grid;

(4) one by one the alternative micro-Black-start Schemes of Electric Power Grid obtaining in step (3) is carried out to simulation calculation, while judging the black start-up course of alternative and lonely network operation, the constraintss such as whether each node voltage of micro-electrical network and micro-mains frequency meet is stablized, safety limit, meet constraints, as feasible scheme, and choose the best alternatives in feasible program.

2. method as claimed in claim 1, is characterized in that, described step (2) is using the distributed power source that meets black entry condition as the alternative unit of black startup power supply, otherwise as being activated the alternative unit of power supply; Specifically comprise:

(2-1) the black entry condition that water wheels unit meets as the alternative unit of black startup power supply is: station service electrical system is working properly; Possesses normal condition for subsequent use; The each portion of unit bearing oil level, oily qualified; Speed regulator forced oil device oil pressure, oil level are in normal range (NR); Machine set outlet switch DC control power supply is normal; The corresponding HV Auxiliary Transformer of unit and on-load switch are normal; Unit and common part control are normal, signal DC power supply is normal; The defect that unit starts without impact;

(2-2) the black entry condition that energy storage equipment/photovoltaic plant meets as the alternative unit of black startup power supply is:

The inverter of energy storage equipment/photovoltaic electric station grid connection possesses islet operation pattern, and anti-isolated island measuring ability exits, and power station entirety meets the code compressor start up condition that puts into operation;

(2-3) the black entry condition that wind-powered electricity generation unit meets as the alternative unit of black startup power supply is:

Wind energy turbine set emergency power supply can meet blower fan auxiliary system power reguirements; Power phase is correct, three-phase voltage balance; Tuning system is in normal condition, anemobiagraph and the wind vane state in normal operation; The oil pressure of the hydraulic means of braking and control system and oil level are in prescribed limit; Gear box oil level and oil temperature are in normal range (NR); Every protective device is all in the correct position of dropping into, and protection definite value all conforms to the value that approval is set; Control power supply in on-position; Control Computer display in normal operating condition; Manually boot on front impeller without the phenomenon of freezing; In cold and humid area, it is qualified that Long-time Shut-down and the wind-powered electricity generation unit newly putting into operation insulate before putting into operation; Through the wind-powered electricity generation unit of maintenance before startup, promising maintenance and the various safety measures set up are removed.

(2-4) black startup Power Selection

A) there is energy-storage units: the energy storage equipment of the first-selected Non-intermittent problem of the black startup power supply of micro-grid system, this also has round-the-clock startup ability in source slightly, not affected by the extraneous factors such as weather.

B) there is voltage regulation and frequency modulation ability: black startup power supply is in having voltage source output characteristic, also there is pressure regulation and frequency modulation function, can ensure the excitatory loss of distribution transformer and micro-grid system ac bus no-load loss, and short-time rating can bear other non-black startup power initiations time impacts.

C) there is enough reserve capacitys: black startup power supply self generating capacity enough, in region, other provides startup power supply without black start-up ability power supply, recovers other generator, and can power to critical load.

(2-5) non-black startup power supply startup sequence

Each micro-source starts and is incorporated in microgrid one by one under Light Condition, to avoid the also net operation of two isolated microgrids; For reducing voltage and the frequency fluctuation in the black start-up course of microgrid, the boot sequence of non-black startup power supply is: micro-grid system first starts and has the micro-source of the voltage-source type of voltage regulation and frequency modulation ability when unloaded, more progressively starts the micro-source of current source type without frequency modulation and voltage modulation ability.

3. the middle control strategy of step (3) specifically comprises as claimed in claim 1:

(3-1) combining inverter control mode

Wind-powered electricity generation, photovoltaic and energy storage equipment are incorporated to AC synchronous electrical network by combining inverter, and inverter control pattern is three classes:

1) inverter PQ control model, for double-fed blower fan, under grid-connected state, now the power stage of inverter is followed wind-force/light conditions, to reach the maximum object of meritorious output;

2) inverter V/f control model, now micro-source is as the frequency modulation/voltage controller power source in orphan's net, and the voltage/frequency that maintains lonely net is stable;

3) the Pf/VQ control model of inverter band droop characteristic, now micro-source can have the regulating characteristics of normal power supplies, meritorious output is with frequency change, idle output changes with voltage magnitude, there is well positive regulating characteristics, be very beneficial for the power division between each micro-power supply in lonely net situation, and without communication.

4. method as claimed in claim 1, is characterized in that, each node voltage and micro-mains frequency of the micro-electrical network of described step (4) meet mains frequency, voltage stabilization condition, specifically comprise:

(4-1) voltage stabilization requirement

In the time of lonely network operation, the automatism voltage control function of the system that puts into excitation AVR, makes the exciting current of generator regulate with the variation of System Reactive Power electric current, thereby keeps the relatively stable of generator voltage;

(4-2) the lonely network operation frequency stabilization of micro-electrical network requirement

Operate in the non-frequency modulation unit in large electrical network, adopt frequency modulation frequency modulation mode, change after power given value P, maintain to reach the object that system frequency is stable by the regulating characteristics of speed regulator; Generator operation, in the time that orphan nets, adopts constant frequency control mode, adopts primary frequency modulation mode; In the time of lonely network operation, trend, the stability etc. of whole lonely net are carried out to analytical calculation, formulate perfect lonely network operation prediction scheme, implement United Dispatching, each node cooperates, and realizes the stable operation of lonely net; Unit in the lonely net of operation, its speed governing, excitation, control, protection system all meet the requirement of lonely network operation.