CN104158201A - Self-organization power flow controlling method of photovoltaic power generator set suitable for power distribution network - Google Patents

Abstract

The invention discloses a self-organization power flow controlling method of a photovoltaic power generator set suitable for a power distribution network. The self-organization power flow controlling method comprises the following steps: the photovoltaic power generator set is controlled; each photovoltaic power generator of the power distribution network is controlled through underlying controlling volumes and communication matrixes; the communication matrixes of a partial communication network are optimized to be complete sequences; the photovoltaic power generator set of the power distribution network is controlled through high-level controlling volumes. According to the invention, a plurality of photovoltaic power generators of the power distribution network can be stable and efficiently controlled under the condition of limit communication ability; active power outputted by the photovoltaic power generators is close to a set value; a system composed of the photovoltaic power generators can be improved in anti-interference; the self-organization power flow controlling method has the characteristic of redundancy in the time-variety and instantaneity of the partial communication network, and the smallest communication bandwidth can be realized.

Description

Be applicable to the photovoltaic generation unit self-organizing power flow control method in power distribution network

Technical field

The present invention relates to a kind of photovoltaic generation unit power flow control method, especially relate to a kind of photovoltaic generation unit self-organizing power flow control method being applicable in power distribution network.

Background technology

In recent years, the permeability of photovoltaic generator in power distribution network increases gradually.Yet relevant stability and control problem make the access of a large amount of photovoltaic generators produce larger negative effect to electric power system.Photovoltaic generation permeability compared with power distribution network high and that energy storage device is less in, the disturbance of certain burst (such as the sudden change of illumination etc.) will cause quick disconnection or the rapid drawdown of output electric energy of photovoltaic generator, this will cause power distribution network to lose active power supporting.The minimizing of active power can cause problems, as voltage fluctuation, and instantaneous stable problem or voltage collapse etc.Therefore, find a kind of robust control strategy of practicality, realize the reliable and stable control of a large amount of distributed photovoltaic power generation machine power outputs in power distribution network, become the problem of needing at present solution badly.

Summary of the invention

For addressing the above problem, the present invention proposes a kind of photovoltaic generation unit self-organizing power flow control method being applicable in power distribution network, efficient control with a large amount of distributed photovoltaic power generation unit power outputs in power distribution network, improve the vulnerability to jamming of power distribution network, stable critical busses voltage and the appointment feeder line active power controlled.

Technical scheme of the present invention adopts following steps:

1) photovoltaic generation unit is controlled, first every photovoltaic generator in the photovoltaic generation unit of power distribution network is controlled by bottom control amount and communication matrix, so that consistent in each photovoltaic generator utilance of the balance point place of power distribution network photovoltaic generation unit;

2) communication matrix of local communication network is optimized for to complete sequence, to improve stability and the validity of power distribution network;

3) the photovoltaic generation unit of power distribution network is controlled by high-rise controlled quentity controlled variable, constant so that the critical busses voltage in every group of photovoltaic generator keeps, make to flow through simultaneously and specify the active power of feeder line to keep constant.

Described step 1) every photovoltaic generator in the photovoltaic generation unit in is controlled by bottom control amount and the communication matrix of following formula 1,

$\left\{\begin{array}{c}{u}_{\mathrm{di}}=\frac{K_0{P}_{i\max }}{U_i}(D_{i0}{\mathrm{\α}}_P^{*}-\frac{P_i}{P_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}{P}_i}{P_{i\max }})-\frac{{\stackrel{\·}{U}}_i{P}_i}{U_i^2}\\ u_{\mathrm{qi}}=-\frac{K_0{Q}_{i\max }}{U_i}(D_{i0}^{\′}{\mathrm{\α}}_Q^{*}-\frac{Q_i}{Q_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}^{\′}{Q}_i}{Q_{i\max }})+\frac{{\stackrel{\·}{U}}_i{Q}_i}{U_i}\end{array}\right.---\left(1\right)$

Wherein, u _di, u _qibe respectively the bottom control rule of controlling photovoltaic generator active power of output and reactive power, be respectively the reference utilance of active power and reactive power, K ₀for bottom control flow gain, and have be respectively the practical efficiency of active power and reactive power, U _i, P _i, Q _ibe respectively the actual value of critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, for U _ifirst derivative, U _imax, P _imax, Q _imaxthe maximum that is respectively critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, i, j represent respectively i platform, j platform photovoltaic generator, i, j, n are positive integer, i=1,2 ..., n, j=1,2 ..., n.

The operator D of the active power communication matrix in above formula 1 _ijoperator D ' with reactive power communication matrix _ijadopt following formula 2 and formula 3 to calculate:

$D_{\mathrm{ij}}=s_{\mathrm{ij}}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}---\left(2\right)$

$D_{\mathrm{ij}}^{\′}=s_{\mathrm{ij}}^{\′}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}^{\′}---\left(3\right)$

Wherein, s _ij, s ' _ijbe respectively the element in the communication matrix S of active power and the communication matrix S ' of reactive power; Then build the communication matrix S of active power and the communication matrix S ' of reactive power of following formula 4 and formula 5:

When i is identical with j, all there is s _ij(t)=1, s ' _ij(t)=1; When the information of j platform photovoltaic generator can be known by i platform photovoltaic generator in the t moment, s _ij(t)=1, s ' _ij(t)=1, otherwise s _ij(t)=0, s ' _ij(t)=0; When i platform photovoltaic generator is when t can receive information constantly from high level is controlled, s _i0(t)=1, s ' _i0(t)=1, otherwise s _i0(t)=0, s ' _i0(t)=0.

The communication matrix of the local communication network described step 2) adopts following formula 6 and formula 7 to be optimized, and forms complete sequence:

S _0:∞＝{S(t ₀),S(t ₁),……,S(t _n)} (6)

S′ _0:∞＝{S′(t ₀),S′(t ₁),……,S′(t _n)} (7)

Wherein, S _{0: ∞}, S ' _{0: ∞}be respectively the complete sequence of active power and reactive power, S (t ₀), S (t ₁) ..., S (t _n) and S ' (t ₀), S ' (t ₁) ..., S ' (t _n) be respectively the communication matrix S of active power and the communication matrix S ' of reactive power at t ₀, t ₁..., t _nexpression constantly.

Described step 3) the photovoltaic generation unit in is controlled by the high-rise controlled quentity controlled variable of following formula 8:

$\left\{\begin{array}{c}{u}_{d0}=K_P(P_{\mathrm{ref}}-P_{\mathrm{tl}})\\ u_{q0}=K_V(V_{\mathrm{ref}}-V_{\mathrm{bus}})\end{array}\right.---\left(8\right)$

Wherein, u _d0, u _q0be respectively active power with reference to utilance and reactive power the high-rise controlled quentity controlled variable with reference to utilance, K _p, K _vbe respectively first, second parameter to be adjusted, V _bus, P _tlbe respectively the actual value of critical busses voltage and appointment feeder line active power, V _ref, P _refbe respectively the reference value of critical busses voltage and appointment feeder line active power.

The invention has the beneficial effects as follows:

The present invention has used for reference the advantage that distributed network cooperative control method communicating requirement is lower, be easy to realize the unified control of distributed unit, the thought of simultaneously controlling by voltage, Feedback of Power, and obtain in conjunction with a large amount of simulation analysis, can realize the power distribution network active power that contains many distributed photovoltaic power generation units and the stable control of reactive power, make the active power of many photovoltaic generator outputs be tending towards set-point, and improved power distribution network robustness and reliability.

The present invention, by the efficient control of a large amount of distributed photovoltaic power generation unit power outputs in power distribution network, improves the vulnerability to jamming of power distribution network, stablizes and controls critical busses voltage and specify feeder line active power; And the time variation of local communication network and instantaneity are had to redundancy properties, and can realize minimal communications bandwidth.

Accompanying drawing explanation

Fig. 1 is that the overall logic of the inventive method is related to block diagram.

Fig. 2 is the control schematic diagram that active power of the present invention adopts high-rise controlled quentity controlled variable.

Fig. 3 is the control schematic diagram that reactive power of the present invention adopts high-rise controlled quentity controlled variable.

Fig. 4 is embodiment emulation illustration intention.

Active power utilance and reactive power utilance when Fig. 5 is the generation of embodiment short trouble.

Critical busses voltage when Fig. 6 is the generation of embodiment short trouble and the active power on feeder line 1.

Active power and the reactive power of photovoltaic generator output when Fig. 7 is the sudden change of embodiment intensity of illumination.

Critical busses voltage when Fig. 8 is the sudden change of embodiment intensity of illumination and the active power on feeder line 1.

Response when Fig. 9 is the load variations of embodiment communication failure when having (dotted line) and not having (solid line).

Key busbar voltage when Figure 10 is the load variations of embodiment communication failure when having (dotted line) and not having (solid line) and the active power on feeder line 1.

Embodiment

Below in conjunction with drawings and the specific embodiments, the present invention is described in further detail.

As shown in Figure 1, the inventive method comprises the following steps:

1) photovoltaic generation unit is controlled, first every photovoltaic generator in the photovoltaic generation unit of power distribution network is controlled by bottom control amount and communication matrix, so that consistent in each photovoltaic generator utilance of the balance point place of power distribution network photovoltaic generation unit;

2) communication matrix of local communication network is optimized for to complete sequence, to improve stability and the validity of power distribution network;

3) the photovoltaic generation unit of power distribution network is controlled by high-rise controlled quentity controlled variable, constant so that the critical busses voltage in every group of photovoltaic generator keeps, make to flow through simultaneously and specify the active power of feeder line to keep constant.

Step 1) every photovoltaic generator in the photovoltaic generation unit in is controlled by bottom control amount and the communication matrix of following formula 1,

$\left\{\begin{array}{c}{u}_{\mathrm{di}}=\frac{K_0{P}_{i\max }}{U_i}(D_{i0}{\mathrm{\α}}_P^{*}-\frac{P_i}{P_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}{P}_i}{P_{i\max }})-\frac{{\stackrel{\·}{U}}_i{P}_i}{U_i^2}\\ u_{\mathrm{qi}}=-\frac{K_0{Q}_{i\max }}{U_i}(D_{i0}^{\′}{\mathrm{\α}}_Q^{*}-\frac{Q_i}{Q_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}^{\′}{Q}_i}{Q_{i\max }})+\frac{{\stackrel{\·}{U}}_i{Q}_i}{U_i}\end{array}\right.---\left(1\right)$

Wherein, u _di, u _qibe respectively the bottom control rule of controlling photovoltaic generator active power of output and reactive power, be respectively the reference utilance of active power and reactive power, K ₀for bottom control flow gain, and have be respectively the practical efficiency of active power and reactive power, U _i, P _i, Q _ibe respectively the actual value of critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, for U _ifirst derivative, U _imax, P _imax, Q _imaxthe maximum that is respectively critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, i, j represent respectively i platform, j platform photovoltaic generator, i, j, n are positive integer, i=1,2 ..., n, j=1,2 ..., n.

The operator D of the active power communication matrix in above formula 1 _ijoperator D ' with reactive power communication matrix _ijadopt following formula 2 and formula 3 to calculate:

$D_{\mathrm{ij}}=s_{\mathrm{ij}}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}---\left(2\right)$

$D_{\mathrm{ij}}^{\′}=s_{\mathrm{ij}}^{\′}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}^{\′}---\left(3\right)$

Wherein, s _ij, s ' _ijbe respectively the element in the communication matrix S of active power and the communication matrix S ' of reactive power; Then build the communication matrix S of active power and the communication matrix S ' of reactive power of following formula 4 and formula 5:

When i is identical with j, all there is s _ij(t)=1, s ' _ij(t)=1; When the information of j platform photovoltaic generator can be known by i platform photovoltaic generator in the t moment, s _ij(t)=1, s ' _ij(t)=1, otherwise s _ij(t)=0, s ' _ij(t)=0; When i platform photovoltaic generator is when t can receive information constantly from high level is controlled, s _i0(t)=1, s ' _i0(t)=1, otherwise s _i0(t)=0, s ' _i0(t)=0.

The communication matrix of the local communication network step 2) adopts following formula 6 and formula 7 to be optimized, and forms complete sequence:

S _0:∞＝{S(t ₀),S(t ₁),……,S(t _n)} (6)

S′ _0:∞＝{S′(t ₀),S′(t ₁),……,S′(t _n)} (7)

Wherein, S _{0: ∞}, S ' _{0: ∞}be respectively the complete sequence of active power and reactive power, S (t ₀), S (t ₁) ..., S (t _n) and S ' (t ₀), S ' (t ₁) ..., S ' (t _n) be respectively the communication matrix S of active power and the communication matrix S ' of reactive power at t ₀, t ₁..., t _nexpression constantly.

As shown in Figure 2 and Figure 3, the photovoltaic generation unit step 3) is controlled by the high-rise controlled quentity controlled variable of following formula 8:

$\left\{\begin{array}{c}{u}_{d0}=K_P(P_{\mathrm{ref}}-P_{\mathrm{tl}})\\ u_{q0}=K_V(V_{\mathrm{ref}}-V_{\mathrm{bus}})\end{array}\right.---\left(8\right)$

Wherein, u _d0, u _q0be respectively active power with reference to utilance and reactive power the high-rise controlled quentity controlled variable with reference to utilance, K _p, K _vbe respectively first, second parameter to be adjusted, V _bus, P _tlbe respectively the actual value of critical busses voltage and appointment feeder line active power, V _ref, P _refbe respectively the reference value of critical busses voltage and appointment feeder line active power.

The present invention is particularly useful for the photovoltaic generation unit self-organizing power flow control in power distribution network.Be first photovoltaic generation unit design bottom control rule and the communication matrix in power distribution network, so that at system balancing point place, photovoltaic generator utilance reaches unanimity; Reducing under the prerequisite of cost, design local communication network, realize stability and the validity of power distribution network; For the high-rise control law reasonable in design of the photovoltaic generation unit in power distribution network, so that for every group of photovoltaic generator, it is constant that critical busses voltage keeps, and the active power of a certain appointment feeder line that simultaneously makes to flow through keeps definite value.

Step 1 of the present invention) by design bottom control rule and communication matrix, can realize many photovoltaic generators in power distribution network has under the prerequisite of higher communication redundancy, the utilance of active power of output and reactive power reaches unanimity, and has improved the stability of distributed photovoltaic power generation unit operation.

Step 2 of the present invention) the local communication network of design power distribution network, not only can improve the power distribution network operation stability and the validity that contain many photovoltaic generators, and can effectively reduce the communications cost of distributed photovoltaic unit, reduces system investment.

Step 3 of the present invention) the high-rise control law of photovoltaic generation unit reasonable in design, so that for every group of photovoltaic generator, it is constant that critical busses voltage keeps, make to flow through certain specifies the active power of feeder line to keep definite value simultaneously.

What the present invention is directed to is the distribution system that contains n three-phase photovoltaic grid-connected generator, ignores the impact of built-in variable on photovoltaic generation unit, and the photovoltaic generation unit dynamic model after simplification is as follows:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{\mathrm{di}}^{\mathrm{ref}}=u_{\mathrm{di}}\\ {\stackrel{\·}{I}}_{\mathrm{qi}}^{\mathrm{ref}}=u_{\mathrm{qi}}\\ P_i=U_i{I}_{\mathrm{di}}\\ Q_i=-U_i{I}_{\mathrm{qi}}\\ g(P_1,...,P_n,Q_1,...,Q_n,\mathrm{\χ},X)=0\end{array}\right.$

Wherein, u _di, u _qifor every control law that photovoltaic generator is to be designed, I _di, I _qifor d, the q axle component actual value of three-phase photovoltaic generator output current, for d, the q axle component reference value of three-phase photovoltaic generator output current, P _i, Q _iactive power and reactive power for the output of three-phase photovoltaic generator, χ has the phasor of specifying all internal state variable of distributed energy (dynamic model that comprises photovoltaic generator, load, synchronous generator etc.) of dimension to form, and Χ is the phasor that algebraically variable in power distribution network (as busbar voltage etc.) forms.

Above formula is the model in power distribution network that contains photovoltaic generation unit, and this model is to be realized, in power distribution network, photovoltaic generation unit is carried out to the known foundation of self-organizing power flow control by the present invention.

Specific embodiments of the invention are as follows:

The control method on the microgrid emulation illustration shown in Fig. 4, the present invention being proposed has been carried out emulation experiment.L-G simulation test parameter is as shown in table 1.

Table 1

In Matlab/Simulink, set up simulation model, the control method that adopts the present invention to propose, gained emulation experiment data: after short trouble occurs, photovoltaic generation unit recovers to be less than 10s stabilization time; After intensity of illumination sudden change, photovoltaic generation unit recovers to be less than 5s stabilization time; After communication failure occurs, photovoltaic generation unit recovers to be less than 20s stabilization time.

Experiment sectional drawing is as follows:

(1) Fig. 5,6 has shown when power distribution network is short-circuited fault, the change procedure of photovoltaic generation unit active power of output, reactive power, critical busses voltage and feeder line 1 power.Visible, short trouble can not exert an influence with property to the stable of system, shows that the control method that the present invention proposes can effectively improve the robustness of power distribution network operation.

(2) when Fig. 7,8 has shown intensity of illumination sudden change, the change procedure of photovoltaic generation unit active power of output, reactive power, critical busses voltage and feeder line 1 power.Visible, the variation of external environment condition can not bring impact to the normal operation of power distribution network, shows that control method that the present invention proposes can obviously improve the operational reliability of photovoltaic generation unit, guarantees the stable operation of distribution system.

(3) Fig. 9,10 has shown power distribution network generation communication failure, and load is when undergo mutation, the change procedure of load variations trend and key busbar voltage, feeder line 1 power.Visible, when power distribution network exists communication failure, show that control method that the present invention proposes still can guarantee effective operation of power distribution network, has improved the communication fault-tolerant ability of power distribution network.

Above-mentioned embodiment is used for the present invention that explains, rather than limits the invention, and in the protection range of spirit of the present invention and claim, any modification and change that the present invention is made, all fall into protection scope of the present invention.

Claims (4)

1. be applicable to the photovoltaic generation unit self-organizing power flow control method in power distribution network, it is characterized in that: comprise the following steps:

1) photovoltaic generation unit is controlled, first every photovoltaic generator in the photovoltaic generation unit of power distribution network is controlled by bottom control amount and communication matrix, so that consistent in each photovoltaic generator utilance of the balance point place of power distribution network photovoltaic generation unit;

2) communication matrix of local communication network is optimized for to complete sequence, to improve stability and the validity of power distribution network;

3) the photovoltaic generation unit of power distribution network is controlled by high-rise controlled quentity controlled variable, constant so that the critical busses voltage in every group of photovoltaic generator keeps, make to flow through simultaneously and specify the active power of feeder line to keep constant.

2. a kind of photovoltaic generation unit self-organizing power flow control method being applicable in power distribution network according to claim 1, is characterized in that: every photovoltaic generator in the photovoltaic generation unit described step 1) is controlled by bottom control amount and the communication matrix of following formula 1:

$\left\{\begin{array}{c}{u}_{\mathrm{di}}=\frac{K_0{P}_{i\max }}{U_i}(D_{i0}{\mathrm{\α}}_P^{*}-\frac{P_i}{P_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}{P}_i}{P_{i\max }})-\frac{{\stackrel{\·}{U}}_i{P}_i}{U_i^2}\\ u_{\mathrm{qi}}=-\frac{K_0{Q}_{i\max }}{U_i}(D_{i0}^{\′}{\mathrm{\α}}_Q^{*}-\frac{Q_i}{Q_{i\max }}+\underset{j=1}{\overset{n}{\mathrm{\Σ}}}\frac{D_{\mathrm{ij}}^{\′}{Q}_i}{Q_{i\max }})+\frac{{\stackrel{\·}{U}}_i{Q}_i}{U_i}\end{array}\right.---\left(1\right)$

Wherein, u _di, u _qibe respectively the bottom control rule of controlling photovoltaic generator active power of output and reactive power, be respectively the reference utilance of active power and reactive power, K ₀for bottom control flow gain, and have be respectively the practical efficiency of active power and reactive power, U _i, P _i, Q _ibe respectively the actual value of critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, for U _ifirst derivative, U _imax, P _imax, Q _imaxthe maximum that is respectively critical busses voltage, appointment feeder line active power and appointment feeder line reactive power, i, j represent respectively i platform, j platform photovoltaic generator, i, j, n are positive integer, i=1,2 ..., n, j=1,2 ..., n.

The operator D of the active power communication matrix in above formula 1 _ijoperator D ' with reactive power communication matrix _ijadopt following formula 2 and formula 3 to calculate:

$D_{\mathrm{ij}}=s_{\mathrm{ij}}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}---\left(2\right)$

$D_{\mathrm{ij}}^{\′}=s_{\mathrm{ij}}^{\′}/\underset{j=0}{\overset{n}{\mathrm{\Σ}}}{s}_{\mathrm{ij}}^{\′}---\left(3\right)$

Wherein, s _ij, s ' _ijbe respectively the element in the communication matrix S of active power and the communication matrix S ' of reactive power; Then build the communication matrix S of active power and the communication matrix S ' of reactive power of following formula 4 and formula 5:

When i is identical with j, all there is s _ij(t)=1, s ' _ij(t)=1; When the information of j platform photovoltaic generator can be known by i platform photovoltaic generator in the t moment, s _ij(t)=1, s ' _ij(t)=1, otherwise s _ij(t)=0, s ' _ij(t)=0; When i platform photovoltaic generator is when t can receive information constantly from high level is controlled, s _i0(t)=1, s ' _i0(t)=1, otherwise s _i0(t)=0, s ' _i0(t)=0.

3. a kind of photovoltaic generation unit self-organizing power flow control method being applicable in power distribution network according to claim 1, it is characterized in that: the communication matrix of the local communication network described step 2) adopts following formula 6 and formula 7 to be optimized, and forms complete sequence:

S _0:∞＝{S(t ₀),S(t ₁),……,S(t _n)} (6)

S′ _0:∞＝{S′(t ₀),S′(t ₁),……,S′(t _n)} (7)

Wherein, S _{0: ∞}, S ' _{0: ∞}be respectively the complete sequence of active power and reactive power, S (t ₀), S (t ₁) ..., S (t _n) and S ' (t ₀), S ' (t ₁) ..., S ' (t _n) be respectively the communication matrix S of active power and the communication matrix S ' of reactive power at t ₀, t ₁..., t _nexpression constantly.

4. a kind of photovoltaic generation unit self-organizing power flow control method being applicable in power distribution network according to claim 1, is characterized in that: the photovoltaic generation unit described step 3) is controlled by the high-rise controlled quentity controlled variable of following formula 8:

$\left\{\begin{array}{c}{u}_{d0}=K_P(P_{\mathrm{ref}}-P_{\mathrm{tl}})\\ u_{q0}=K_V(V_{\mathrm{ref}}-V_{\mathrm{bus}})\end{array}\right.---\left(8\right)$

Wherein, u _d0, u _q0be respectively active power with reference to utilance and reactive power the high-rise controlled quentity controlled variable with reference to utilance, K _p, K _vbe respectively first, second parameter to be adjusted, V _bus, P _tlbe respectively the actual value of critical busses voltage and appointment feeder line active power, V _ref, P _refbe respectively the reference value of critical busses voltage and appointment feeder line active power.