CN105680442A - Expected energy not supplied evaluation method for power flow and sensitivity consistency-based equivalent network - Google Patents

Abstract

The invention provides an expected energy not supplied evaluation method for a power flow and sensitivity consistency-based equivalent network, namely a rapid reliability evaluation method by considering power flow and sensitivity consistency equivalence. By a computer, basic data of a network and intranet reliability evaluation parameters are firstly input through a program; the equivalent network is obtained through a static equivalent method of the power flow and sensitivity consistency; equivalent network parameters are calculated; a topology analysis model containing the equivalent network for intranet reliability evaluation is built; an intranet system state is sampled by a monte-carlo method; the minimum load shedding amount of each sampling state is calculated on the basis of the topology analysis model containing the equivalent network; and an intranet reliability index EENS is finally obtained by statistics.

Description

Delivery appraisal procedure is lacked based on the expectation considering trend and sensitivity concordance equivalent network

Technical field

The present invention relates to and lack delivery appraisal procedure for electrical domain, particularly a kind of expectation for equivalent network.

Background technology

Along with the greatly developing of new forms of energy, constantly the advancing and the continuous growth of load of electricity market, power system is developing progressively the interconnected power grid for being closely connected again between layering and zoning and each subregion. Day by day strengthen owing to influencing each other between each subnet, the impact of interconnection outer net effectively must be considered when the subnet (i.e. Intranet) studied is analyzed decision-making; But in some cases, due to technical reason or relate to the problems such as industry confidentiality, electric network data between system subnet, can not be shared, cause and system cannot be carried out between each subnet complete data exchange. Therefore, interconnected subnetworks information can be retained there is again the Equivalent Model of good security performance be widely used in interconnected network analytical calculation.

In the index of reliability assessment calculates, trend and sensitivity are the important informations needed for systematic analysis and minimum tangential load calculating, the concordance of trend and sensitivity before and after equivalence should be taken into full account, the effectiveness of reliability index computational accuracy and operational decisions thereof to ensure Intranet when setting up Equivalent Model.

The existing reliability estimation method considering equivalence generally all only considered the concordance of trend before and after equivalence, but does not account for the concordance of sensitivity before and after equivalence. Such as " ApplicationofanAdequacyEquivalentMethodinBulkPowerSystem ReliabilityEvaluation " literary composition delivered on IEEETransactionsonPowerSystem in May, 1998, this article utilizes abundant intensity equivalence method that urban core electrical network is carried out reliability assessment. Abundant intensity equivalence method is a kind of equivalent machine method of simple extension, external network equivalent is become injection current by it, the method meets the concordance of equivalent front and back trend, but it is difficult to ensure that the concordance of sensitivity, and do not account for the rack characteristic of outer net, when system changes, it is impossible to be effectively ensured the computational accuracy of systematic analysis and minimum tangential load, thus affecting the accuracy of reliability assessment.

EENS (expectedenergynotsupplied), has another name called expectation and lacks delivery, refers to that system causes the expectation number of workload demand energy curtlaiment in interval endogenous cause of ill generating capacity shortage preset time or power constraint. EENS index is one of Reliability Index, and the probability having a power failure, scope, persistent period are tightly relevant, are utilized to the overload of reflection system reliability Billy's bus or power transmission line more accurately comprehensively.

Summary of the invention

It is an object of the invention to provide a kind of based on the scarce delivery appraisal procedure of the expectation considering trend and sensitivity concordance equivalent network, it can calculate expectation under considering trend and the conforming situation of sensitivity and lack delivery appraisal procedure.

It is an object of the invention to be realized by such technical scheme, specifically comprise the following steps that

1) interconnected network basic data and reliability assessment parameter are gathered;

2) adopt based on the conforming static equivalence method of trend and sensitivity, calculate the equivalent parameters of equivalent network, set up the topology analysis model of equivalent network;

3) according to step 2) in gained topology analysis model and constraints, set up the correction minimum load shedding model equivalent based on trend, sensitivity and constraint concordance, and solve;

4) expectation of reliability assessment index lacks delivery EENS calculating.

2. as claimed in claim 1 based on the scarce delivery appraisal procedure of the expectation considering trend and sensitivity concordance equivalent network, it is characterized in that, internetwork node is divided into three parts, respectively outer net node set E, boundary node set B and Intranet node set I;

Step 1) described in interconnected network basic data include interconnected network topological structure and power equipment parameter, reliability assessment parameter includes the availability of interior mesh element number and each element;

Described power equipment parameter includes impedance parameter and susceptance parameter, the impedance parameter of transformator, over the ground admittance parameter and no-load voltage ratio parameter, the admittance parameter over the ground of whole nodes, generator output constraints, the line transmission constraints over the ground of whole circuit.

3. as claimed in claim 2 lack delivery appraisal procedure in the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 2) described in equivalent parameters include branch impedanceWith equivalence branch admittance over the groundDeng duty valueValue generator output

4. as claimed in claim 3 lack delivery appraisal procedure in the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 3) described in revise minimum load shedding model and be

$\min \underset{k=1}{\overset{M_I+N_B}{\mathrm{\Σ}}}{C}_k---\left(11\right)$

In formula, C_kFor the cutting load amount of Intranet or boundary node k, N_I,N_BRespectively Intranet and boundary node quantity;

Step 3) described in Semen Phaseoli condition include:

3-1) trend Constraints of Equilibrium

$\begin{array}{c}{Q}_{Gi}+Q_{cri}-Q_{Di}+C_k{Q}_{Dk}/P_{Dk}-V_i\underset{j=1}{\overset{N_B}{\mathrm{\Σ}}}{V}_j(G_{ij}{\mathrm{sin\δ}}_{ij}-B_{ij}{\mathrm{cos\δ}}_{ij})=0\\ (i=1,...,N,k=1,...,N_I+N_B)\end{array}---\left(13\right)$

In formula: i ∈ (I, B, eq), P_GiExport for generated power, P_DiFor the load active power of node i, Q_GiExport for generator reactive, Q_DiFor the reactive load power of node i, Q_criCompensate for parallel reactive and inject reactive power, V_iFor the on high-tension side voltage of external node, V_jFor the voltage of external node low-pressure side, G_ijFor the conductance between external node i and j, B_ijFor the susceptance between external node i and j, δ_ijFor the phase angle difference between external node i and j, N is the whole network number of nodes after equivalence, N_BFor the original nodes of system, N_SFor balance node;

3-2) Intranet variable bound

k_Itmin≤k_It≤k_ItmaxT=1 ..., N_T(14)

P_IGimin≤P_IGi≤P_IGimaxI=1 ..., N_G(15)

Q_IGimin≤Q_IGi≤Q_IGimaxI=1 ..., N_G(16)

Q_Icrimin≤Q_Icri≤Q_IcrimaxI=1 ..., N_cr(17)

In formula (4)～(7), k_ItFor Intranet ULTC LTC no-load voltage ratio, k_Itmin,k_ItmaxFor k_ItBound constraint, N_TNumber for Intranet ULTC LTC;P_IGiAnd Q_IGiMeritorious and idle for the output of Intranet electromotor, P_IGimin,P_IGimaxAnd Q_IGimin,Q_IGimaxIt is P respectively_IGiAnd Q_IGiBound constraint, N_GNumber for Intranet electromotor; Q_IcriCompensate for Intranet parallel reactive, Q_Icrimin,Q_IcrimaxFor Q_IcriBound constraint, N_crThe number of equipment is compensated for parallel reactive;

3-3) node burden with power abatement amount constraint

0≤C_k≤P_DkK=1 ..., N_I+N_B(18)

So far, the correction minimum load shedding model equivalent based on trend and sensitivity concordance has been set up, and adopts prediction prim al-dual interior point m ethod that this minimum load shedding model is solved.

5. as described in claim 4 lack delivery appraisal procedure based on the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 4) described in the computational methods of EENS as follows:

4-1) select Intranet system mode

Adopting Monte Carlo method that system mode is sampled, if sampling total degree is M time, what extract is all a completely self-contained state every time, then the system mode probability extracted each time is as follows:

$P_x=\frac{1}{M}---\left(19\right)$

4-2) topological analysis

After having selected system mode, system is carried out topological analysis, the node and branch road that have electrical link are divided in a subsystem, and sort out the data of each subsystem, to form the input data that voltage stabilization Corrective control is analyzed; If when system not off-the-line, the whole network is a system, if for the system of off-the-line, getting rid of the network of smaller portions, retains big network;

4-3) total EENS index calculates;

$EENS=\underset{i\∈S}{\mathrm{\Σ}}{C}_i{P}_{i}T---\left(20\right)$

In formula: S is the system mode complete or collected works that can not meet workload demand in the preset time of interval; P_iThe probability of state i it is in for system; C_iThe load power cut down when for state i; T is 8760h. Expect that lacking delivery unit represents typically by MW h/a.

6. as claimed in claim 5 based on the scarce delivery appraisal procedure of the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 4-2) after the whole network is a system or reservation macroreticular, further comprising the steps of:

A, calculating trend distribution, whether difference is out-of-limit, or out-of-limit, then proceed to step B, if not out-of-limit, proceeds to step E;

B, employing adjustment means, it determines whether out-of-limit, if out-of-limit, proceed to step C, if not out-of-limit, proceed to step E;

C, adopt optimized algorithm to carry out minimum lotus scheme of cutting to process, arrange Intranet all can total cutting load amount of cutting load node minimum for optimization aim, it is considered to the constraints such as network power Constraints of Equilibrium after the constraint of interior mesh element and equivalence, set up Optimized model; Then adopt prediction prim al-dual interior point m ethod that Optimized model is solved, it is judged that whether minimum tangential load scheme restrains and whether scheme is unique, if then proceeding to step D, if not ignoring this system mode situation and proceeding to step E; ;

D, computing system state X EENS index, and proceed to step E;

E, judging whether to meet the Monte Carlo method condition of convergence, if meeting, then proceeding to step F;

F, proceed to step 4-3).

Owing to have employed technique scheme, present invention have the advantage that:

1, in setting up the Intranet reliability assessment topology analysis model containing equivalent network, external network equivalent method of the present invention can not only keep the concordance of trend before and after equivalence, sensitivity concordance before and after equivalence can also be effectively ensured, be effectively increased the accuracy of Intranet reliability assessment topology analysis model containing equivalent network;

2, compared to the existing reliability estimation method based on on-hook Theory of Equivalence and Ward Theory of Equivalence, the topology analysis model that the present invention sets up can be effectively retained outer net to characteristics such as the power transfers between the power of Intranet, voltage support and boundary node, make to analyze more accurate for the Load flow calculation of system mode, minimum tangential load etc., thus ensureing effectiveness and the accuracy of reliability index.

Other advantages of the present invention, target and feature will be illustrated to a certain extent in the following description, and to a certain extent, will be apparent to those skilled in the art based on to investigating hereafter, or can be instructed from the practice of the present invention.The target of the present invention and other advantages can be realized by description below and claims and obtain.

Accompanying drawing explanation

The accompanying drawing of the present invention illustrates as follows.

Fig. 1 is the schematic flow sheet of the present invention;

Fig. 2 is step 2) medium value circuit diagram;

Fig. 3 is node standard test system figure.

Detailed description of the invention

Below in conjunction with drawings and Examples, the invention will be further described.

The present invention adopts trend and the conforming static equivalence method of sensitivity before and after the maintenance equivalence that in " IEEETRANSACTIONSONPOWERSYSTEM " of the 29th volume the 5th phase in 2014, " StaticEquivalentMethodBasedonComponentParticularityRepre sentationandSensitivityConsistency " is proposed to obtain equivalent network and parameter thereof, sets up the topology analysis model of Intranet reliability assessment containing equivalent network. Use Monte Carlo method that Intranet system mode is sampled, calculate and obtain reliability index accurately.

Consider trend and the fast reliability evaluation method of sensitivity concordance equivalence. Utilize computer, by program, first input basic data and the Intranet reliability assessment parameter of network. Obtain equivalent network by the conforming static equivalence method of trend and sensitivity, and calculate equivalent network parameter, the topology analysis model of the foundation Intranet reliability assessment containing equivalent network. Using Monte Carlo method that Intranet system mode is sampled, and calculate the minimum tangential load amount of each sample mode based on the topology analysis model containing equivalent network, finally statistics obtains Intranet reliability index EENS. Its concrete grammar step is as follows:

1) input basic data and reliability assessment parameter

Input interconnected network basic data, including interconnected network topological structure, the i.e. annexation of each node and power equipment parameter in sub area division situation and electrical network, the i.e. impedance parameter of whole circuits and susceptance parameter over the ground, the impedance parameter of transformator, over the ground admittance parameter and no-load voltage ratio parameter, the admittance parameter over the ground of whole nodes, generator output constraints, line transmission constraints etc. Internetwork node before equivalent is divided into three parts, respectively outer net node set E, boundary node set B and Intranet node set I.

Input reliability assessment parameter, including interior mesh element number, i.e. the availability of total element number and available components number and each element, the i.e. degree of unavailability of the availability of available components and unavailable element.

2) topology analysis model containing equivalent network is set up

Adopt existing based on the conforming static equivalence method of trend and sensitivity, i.e. " StaticEquivalentMethodBasedonComponentParticularityRepre sentationandSensitivityConsistency ", calculate the equivalent parameters of medium value network of the present invention, including equivalent branch impedanceWith equivalence branch admittance over the groundDeng duty valueValue generator outputDeng.

After calculating equivalent parameters, it is possible to drawing equivalent network figure as shown in Figure 2, so far the topology analysis model containing equivalent network is just successfully established.

In figure, the branch road between 3 nodes and 4 nodes disconnects, and the branch road between 8 nodes and 9 nodes disconnects. 22 nodes and 29 nodes are boundary node; 4-8,18-21 node is external node; 1-3,9-17,23-28 and 30-57 node is internal node, and its interior joint 1 is balance node.

3) correction minimum load shedding model is set up

Based on step 2) step obtain the topology analysis model containing equivalent network, namely include the constraintss such as the voltage of boundary node, electromotor and line power in conjunction with Intranet, set up the correction minimum load shedding model equivalent based on trend, sensitivity and constraint concordance.

1) object function

Owing to outer net is substituted by equivalent network, therefore after equivalence, the object function of minimum tangential load amount is represented by;

$\min \underset{k=1}{\overset{N_I+N_B}{\mathrm{\Σ}}}{C}_k---\left(21\right)$

In formula, C_kFor the cutting load amount of Intranet or boundary node k, N_I,N_BRespectively Intranet and boundary node quantity.

2) constraints

A. trend Constraints of Equilibrium

$\begin{array}{c}{Q}_{Gi}+Q_{cri}-Q_{Di}+C_k{Q}_{Dk}/P_{Dk}-V_i\underset{j=1}{\overset{N_B}{\mathrm{\Σ}}}{V}_j(G_{ij}{\mathrm{sin\δ}}_{ij}-B_{ij}{\mathrm{cos\δ}}_{ij})=0\\ (i=1,...,N,k=1,...,N_I+N_B)\end{array}---\left(23\right)$

In formula: i ∈ (I, B, eq), P_GiExport for generated power, P_DiFor the load active power of node i, Q_GiExport for generator reactive, Q_DiFor the reactive load power of node i, Q_criCompensate for parallel reactive and inject reactive power, V_iFor the on high-tension side voltage of external node, V_jFor the voltage of external node low-pressure side, G_ijFor the conductance between external node i and j, B_ijFor the susceptance between external node i and j, δ_ijFor the phase angle difference between external node i and j, N is the whole network number of nodes after equivalence, N_BFor the original nodes of system, N_SFor balance node.

B. Intranet variable bound

k_Itmin≤k_It≤k_ItmaxT=1 ..., N_T(24)

P_IGimin≤P_IGi≤P_IGimaxI=1 ..., N_G(25)

Q_IGimin≤Q_IGi≤Q_IGimaxI=1 ..., N_G(26)

Q_Icrimin≤Q_Icri≤Q_IcrimaxI=1 ..., N_cr(27)

In formula (4)～(7), k_ItFor Intranet ULTC LTC no-load voltage ratio, k_Itmin,k_ItmaxFor k_ItBound constraint, N_TNumber for Intranet ULTC LTC; P_IGiAnd Q_IGiMeritorious and idle for the output of Intranet electromotor, P_IGimin,P_IGimaxAnd Q_IGimin,Q_IGimaxIt is P respectively_IGiAnd Q_IGiBound constraint, N_GNumber for Intranet electromotor; Q_IcriCompensate for Intranet parallel reactive, Q_Icrimin,Q_IcrimaxFor Q_IcriBound constraint, N_crThe number of equipment is compensated for parallel reactive.

C. node burden with power reduction constraint

0≤C_k≤P_DkK=1 ..., N_I+N_B(28)

So far, set up based on the correction minimum load shedding model that trend and sensitivity concordance are equivalent. The present invention adopts prediction this minimum load shedding model of prim al-dual interior point m ethod to solve.

4) reliability assessment index calculates

After completing the work of above 3 steps, it is possible to carry out reliability assessment index calculating, the reliability index that the present invention calculates is EENS. EENS, has another name called expectation and lacks delivery, refers to that system causes the expectation number of workload demand energy curtlaiment in interval endogenous cause of ill generating capacity shortage preset time or power constraint.

4-1) select Intranet system mode

The present invention adopts Monte Carlo method that system mode is sampled, and basic ideas are to use random number sequence to produce a series of experiment sample. When sample size is sufficiently large, according to central limit theorem or the law of large numbers, sample average can as the unbiased esti-mator of mathematic expectaion. The variance of sample average is a mark of estimated accuracy. If sampling total degree is M time, what extract is all a completely self-contained state every time, then the system mode probability extracted each time is as follows:

$P_x=\frac{1}{M}---\left(29\right)$

In the sampling process of Monte Carlo, load is also required to stochastic sampling, even if the place of system jam is identical, but due to the undulatory property of load, the state every time extracted also is not quite similar. Therefore in the present invention, it is assumed that the state extracted is all completely self-contained every time, then the probability of each system mode is just as.

4-2) topological analysis

After having selected system mode, it is accomplished by system is carried out topological analysis, its task seeks to analyze the node of whole system and is connected into how many subsystems by circuit and transformator, the node and the branch road that are about to have electrical link are divided in a subsystem, and sort out the related data of each subsystem, to form the input data that voltage stabilization Corrective control is analyzed. When system not off-the-line, the whole network is a system. For the system of off-the-line, get rid of the network of smaller portions, retain big network.

4-3) EENS index calculates

EENS index is one of Reliability Index, and the probability having a power failure, scope, persistent period are tightly relevant, are utilized to the overload of reflection system reliability Billy's bus or power transmission line more accurately comprehensively.The computing formula of Reliability Index EENS is as follows:

$EENS=\underset{i\∈S}{\mathrm{\Σ}}{C}_i{P}_{i}T---\left(30\right)$

In formula: S is the system mode complete or collected works that can not meet workload demand in the preset time of interval; P_iThe probability of state i it is in for system; C_iThe load power cut down when for state i; T is 8760h. Expect that lacking delivery unit represents typically by MW h/a.

Owing to EENS index is a summation amount, if two system modes extracted are identical, its minimum tangential load amount is also identical, therefore the minimum tangential load amount of this two states can be combined the minimum tangential load amount become under a system mode automatically is calculated.

Embodiment:

(1) input basic data and reliability assessment parameter

Internetwork node before equivalent is divided into three parts, respectively outer net node set E={4-8,18-21}, boundary node set B={22,29} and Intranet node set I={1-3,9-17,23-28,30-57}. First inputting the basic data of system shown in Figure 3, wherein, interconnected network basic data includes topological structure and power equipment parameter, and reference capacity is 100MW, referring primarily to IEEE-57 modular system.

Secondly, inputting reliability assessment parameter, the available components number of IEEE57 node modular system is 70, including the number of interior mesh element number and border non-equivalent element. The availability of each available components is as shown in the table:

The availability table of table 1 system element

Element	Electromotor	Circuit	Transformator	Shunt capacitance	Parallel reactance
						Availability	0.008	0.01	0.01	0.008	0.008

(2) topology analysis model containing equivalent network is set up

After (1st) step completes, in this embodiment, adopt existing based on the conforming static equivalence method of trend and sensitivity, i.e. " StaticEquivalentMethodBasedonComponentParticularityRepre sentationandSensitivityConsistency ", calculate the equivalent parameters of medium value network of the present invention, including equivalent branch impedance Z_eq22、Z_eq29And Z_Eq58,59, equivalence is branch admittance over the groundWithDeng duty value P_eqL22And P_eqL29。

Equivalent parameters is as shown in the table:

Table 2 (p.u) external network equivalent parameter list

(3) correction minimum load shedding model is set up

Based on the topology analysis model containing equivalent network that (2nd) step obtains, include the constraintss such as the voltage of boundary node, electromotor and line power in conjunction with Intranet, set up the correction minimum load shedding model equivalent based on trend, sensitivity and constraint concordance.

Consider trend Constraints of Equilibrium formula (2) and formula (3), Intranet variable bound formula (4), (5), (6) and (7) and node burden with power reduction constraints formula (8), the minimum tangential load amount obtaining system can be calculated according to formula (1). Utilizing new outer net static equivalence method in the network of 57 nodes, adopt Monte Carlo method sampling, can calculate the minimum tangential load amount obtained under various states, wherein the minimum tangential load amount of partial status is:

Table 3 (unit: p.u)

(4) reliability index calculates

After completing the work of above 3 steps, it is possible to carry out reliability index calculating, the reliability index that the present invention calculates lacks delivery EENS index for expectation.

1) Intranet system mode is selected

The present invention adopts Monte Carlo method that system mode is sampled, and basic ideas are to use random number sequence to produce a series of experiment sample. When sample size is sufficiently large, according to central limit theorem or the law of large numbers, sample average can as the unbiased esti-mator of mathematic expectaion. In the present invention, Monte Carlo sampling number of times is set to 15000 times, and what extract is all a completely self-contained state every time, then the system mode probability extracted each time is:

$P_x=\frac{1}{M}---\left(31\right)$

In the sampling process of Monte Carlo, load is also required to stochastic sampling, even if the place of system jam is identical, but due to the undulatory property of load, the state every time extracted also is not quite similar.Therefore in the present invention, it is assumed that the state extracted is all completely self-contained every time, then the probability of each system mode is just as.

2) topological analysis

After having selected system mode, it is accomplished by system is carried out topological analysis, its task seeks to analyze the node of whole system and is connected into how many subsystems by circuit and transformator, the node and the branch road that are about to have electrical link are divided in a subsystem, and sort out the related data of each subsystem, to form the input data that voltage stabilization Corrective control is analyzed. When system not off-the-line, the whole network is a system. For the system of off-the-line, get rid of the network of smaller portions, retain big network.

3) EENS index calculates

EENS index is one of Reliability Index, and the probability having a power failure, scope, persistent period are tightly relevant, are utilized to the overload of reflection system reliability Billy's bus or power transmission line more accurately comprehensively. The computing formula of Reliability Index EENS is as follows:

$EENS=\underset{i\∈S}{\mathrm{\Σ}}{C}_i{P}_{i}T$

The several method participating in comparing is as follows:

M0: original the whole network calculates

M1: the inventive method;

M2: be left out the simple of outer net constraint and hang equivalence method the most frequently used in equivalent machine method engineering;

M3: consider the equivalence method of outer net constraint based on the equivalence method that ward is equivalent.

Now two indexs that can reflect external network equivalent precision of definition, absolute error e₁And relative error e₂, the numerical value of the two index is more little, illustrates that precision is more high.

Absolute error e₁:

e₁=| x-x_eq|

Relative error e₂:

$e_2=\left|\frac{x-x_{eq}}{x}\right|\×100\%$

Wherein, x and x_eqRepresent true value and estimated value respectively, so-called true value refers under simulated conditions, inside and outside all adopt the reliability index value of calculation of detailed network model, and estimated value refers to and adopts detailed network model in Intranet, and outer net adopts the reliability index value of calculation under equivalent network model.

1. adopt method M1-M3 calculated EENS index as shown in table 6.

The calculated EENS index of table 6 method M0-M3

Equivalence method	M0	M1	M2	M3
					EENS result (MW h/a)	23545	22640	19288	25121

2. adopt method M1-M3 calculated EENS scale error analysis as shown in table 7.

The calculated EENS scale error of table 7 method M1-M3 is analyzed

From experimental result: after using the fast reliability evaluation method equivalent based on trend and sensitivity concordance that the present invention proposes, the Error Calculation result of Reliability Index is all very little.

In sum, the fast reliability evaluation method computational accuracy equivalent based on trend and sensitivity concordance that the inventive method proposes is higher than that existing to be left out sensitivity conforming containing equivalent reliability index calculating method, the ruuning situation of actual outer net can be simulated well, suitable power and voltage support is provided, to ensure the safety and stability economical operation of interconnected network to Intranet.

What finally illustrate is, above example is only in order to illustrate technical scheme and unrestricted, although the present invention being described in detail with reference to preferred embodiment, it will be understood by those within the art that, technical scheme can be modified or equivalent replacement, without deviating from objective and the scope of the technical program, it all should be encompassed in the middle of scope of the presently claimed invention.

Claims (6)

1. one kind lacks delivery appraisal procedure based on the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that specifically comprise the following steps that

1) interconnected network basic data and reliability assessment parameter are gathered;

2) adopt based on the conforming static equivalence method of trend and sensitivity, calculate the equivalent parameters of equivalent network, set up the topology analysis model of equivalent network;

3) according to step 2) in gained topology analysis model and constraints, set up the correction minimum load shedding model equivalent based on trend, sensitivity and constraint concordance, and solve;

4) expectation of reliability assessment index lacks delivery EENS calculating.

2. as claimed in claim 1 based on the scarce delivery appraisal procedure of the expectation considering trend and sensitivity concordance equivalent network, it is characterized in that, internetwork node is divided into three parts, respectively outer net node set E, boundary node set B and Intranet node set I;

Step 1) described in interconnected network basic data include interconnected network topological structure and power equipment parameter, reliability assessment parameter includes the availability of interior mesh element number and each element;

Described power equipment parameter includes impedance parameter and susceptance parameter, the impedance parameter of transformator, over the ground admittance parameter and no-load voltage ratio parameter, the admittance parameter over the ground of whole nodes, generator output constraints, the line transmission constraints over the ground of whole circuit.

3. as claimed in claim 2 lack delivery appraisal procedure in the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 2) described in equivalent parameters include branch impedanceWith equivalence branch admittance over the groundDeng duty valueValue generator output S_eqGi。

4. as claimed in claim 3 lack delivery appraisal procedure in the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 3) described in revise minimum load shedding model and be

$min\underset{k=1}{\overset{N_I+N_B}{\Σ}}{C}_k---\left(1\right)$

In formula, C_kFor the cutting load amount of Intranet or boundary node k, N_I,N_BRespectively Intranet and boundary node quantity;

Step 3) described in Semen Phaseoli condition include:

3-1) trend Constraints of Equilibrium

$P_{Gi}-P_{Di}+C_k-V_i\underset{j=1}{\overset{N_B}{\Σ}}{V}_j(G_{ij}{\mathrm{cos\δ}}_{ij}+B_{ij}{\mathrm{sin\δ}}_{ij})=0---\left(2\right)$

(i=1 ..., N and i ≠ Ns; K=1 ..., N_I+N_B)

$Q_{Gi}+Q_{cri}-Q_{Di}+C_k{Q}_{Dk}/P_{Dk}-V_i\underset{j=1}{\overset{N_B}{\Σ}}{V}_j(G_{ij}{\mathrm{sin\δ}}_{ij}-B_{ij}{\mathrm{cos\δ}}_{ij})=0---\left(3\right)$

(i=1 ..., N, k=1 ..., N_I+N_B)

In formula: i ∈ (I, B, eq), P_GiExport for generated power, P_DiFor the load active power of node i, Q_GiExport for generator reactive, Q_DiFor the reactive load power of node i, Q_criCompensate for parallel reactive and inject reactive power, V_iFor the on high-tension side voltage of external node, V_jFor the voltage of external node low-pressure side, G_ijFor the conductance between external node i and j, B_ijFor the susceptance between external node i and j, δ_ijFor the phase angle difference between external node i and j, N is the whole network number of nodes after equivalence, N_BFor the original nodes of system, N_SFor balance node;

3-2) Intranet variable bound

k_Itmin≤k_It≤k_ItmaxT=1 ..., N_T(4)

P_IGimin≤P_IGi≤P_IGimaxI=1 ..., N_G(5)

Q_IGimin≤Q_IGi≤Q_IGimaxI=1 ..., N_G(6)

Q_Icrimin≤Q_Icri≤Q_IcrimaxI=1 ..., N_cr(7)

In formula (4)～(7), k_ItFor Intranet ULTC LTC no-load voltage ratio, k_Itmin,k_ItmaxFor k_ItBound constraint, N_TNumber for Intranet ULTC LTC; P_IGiAnd Q_IGiMeritorious and idle for the output of Intranet electromotor, P_IGimin,P_IGimaxAnd Q_IGimin,Q_IGimaxIt is P respectively_IGiAnd Q_IGiBound constraint, N_GNumber for Intranet electromotor; Q_IcriCompensate for Intranet parallel reactive, Q_Icrimin,Q_IcrimaxFor Q_IcriBound constraint, N_crThe number of equipment is compensated for parallel reactive;

3-3) node burden with power abatement amount constraint

0≤C_k≤P_DkK=1 ..., N_I+N_B(8)

So far, the correction minimum load shedding model equivalent based on trend and sensitivity concordance has been set up, and adopts prediction prim al-dual interior point m ethod that this minimum load shedding model is solved.

5. as described in claim 4 lack delivery appraisal procedure based on the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 4) described in the computational methods of EENS as follows:

4-1) select Intranet system mode

Adopting Monte Carlo method that system mode is sampled, if sampling total degree is M time, what extract is all a completely self-contained state every time, then the system mode probability extracted each time is as follows:

$P_x=\frac{1}{M}---\left(9\right)$

4-2) topological analysis

After having selected system mode, system is carried out topological analysis, the node and branch road that have electrical link are divided in a subsystem, and sort out the data of each subsystem, to form the input data that voltage stabilization Corrective control is analyzed;If when system not off-the-line, the whole network is a system, if for the system of off-the-line, getting rid of the network of smaller portions, retains big network;

4-3) total EENS index calculates;

$EENS=\underset{i\∈S}{\Σ}{C}_i{P}_{i}T---\left(10\right)$

In formula: S is the system mode complete or collected works that can not meet workload demand in the preset time of interval; P_iThe probability of state i it is in for system; C_iThe load power cut down when for state i; T is 8760h. Expect that lacking delivery unit represents typically by MW h/a.

6. as claimed in claim 5 based on the scarce delivery appraisal procedure of the expectation considering trend and sensitivity concordance equivalent network, it is characterised in that step 4-2) after the whole network is a system or reservation macroreticular, further comprising the steps of:

A, calculating trend distribution, whether difference is out-of-limit, or out-of-limit, then proceed to step B, if not out-of-limit, proceeds to step E;

B, employing adjustment means, it determines whether out-of-limit, if out-of-limit, proceed to step C, if not out-of-limit, proceed to step E;

C, adopt optimized algorithm to carry out minimum lotus scheme of cutting to process, arrange Intranet all can total cutting load amount of cutting load node minimum for optimization aim, it is considered to the constraints such as network power Constraints of Equilibrium after the constraint of interior mesh element and equivalence, set up Optimized model; Then adopt prediction prim al-dual interior point m ethod that Optimized model is solved, it is judged that whether minimum tangential load scheme restrains and whether scheme is unique, if then proceeding to step D, if not ignoring this system mode situation and proceeding to step E; ;

D, computing system state X EENS index, and proceed to step E;

E, judging whether to meet the Monte Carlo method condition of convergence, if meeting, then proceeding to step F;

F, proceed to step 4-3).