CN103761682B - Configuration method of electric system phasor measuring units - Google Patents

Abstract

Provided is a configuration method of electric system phasor measuring units. The configuration method of the electric system phasor measuring units comprises the steps that sorting is carried out on vulnerability indexes of nodes in a power grid, the nodes are classified according to the sequence of the vulnerability indexes, configuration of the PMUs is carried out on the basis of the maximum tree principle according to plans of the number of the PMUs, to be configured, in each sub-region, and after configuration of the PMUs meets the requirement for complete observability, the PMU check and installation design is carried out on vulnerability components in the process that N-1 faults happen. According to the configuration method of the electric system phasor measuring units, due to the fact that the maximum tree principle is used for carrying out optimal configuration on the PMUs, the global optimal solution can be obtained rapidly, and the purposes that the PMUs are configured in a phased mode under the condition that observation cannot be carried out, and observability and economy of configuration are ensured at the same time when the N-1 faults happen are achieved; good balance among economy, safety and the time benefit is achieved, the conditions of partial areas, with assembled PMUs, in an existing power grid are taken into full consideration, flexibility is good, and implementation performance is good.

Description

A kind of collocation method of power system phasor measurement unit

Technical field

The present invention relates to a kind of (Phasor Measurement of phasor measurement unit stage by stage based on maximum tree theory Unit, PMU) optimal configuration method, belong to field of measuring technique.

Background technology

Phasor measurement unit PMU utilizes the analog voltage of gps signal synchronous acquisition time second level, current signal, obtains voltage With amplitude and the phase angle of current signal, and send it to the data concentrator of control centre, so that control centre can be obtained whole The synchronized phasor of individual electrical network, for real-time monitoring, protection and control etc. use, therefore PMU be considered as power system future Important measuring apparatus.

PMU, as the basic device realizing phasor measuring technique, may be mounted at the different location selected in power system, But under existing technical conditions and restricted economic put into, currently all measurement point can't be installed by phasor measuring set in fact. And, the research of existing PMU allocation plan shows：As long as installing PMU on partly specific bus, you can by these What the metrical information obtained by PMU was related with Circuit theory be derived by power system all phasor information completely considerable.

The method of the existing PMU configuration realizing ornamental, including simulated annealing (SA), genetic algorithm, TABU search Method (TS), particle group optimizing method (PSO) etc., the maximum deficiency that these methods exist is that convergence rate is slow, needs that grows very much to hold The row time, and be difficult to obtain globally optimal solution, limit their applications in actual large-scale power system.

Content of the invention

Present invention aims to the drawback of prior art, provide a kind of can be with the electricity of quick obtaining globally optimal solution The collocation method of Force system phasor measurement unit.

Problem of the present invention is to be realized with following technical proposals：

A kind of collocation method of power system phasor measurement unit, the vulnerability first to node each in electrical network for the methods described Index is ranked up, and according to the size of vulnerability inder, each node is classified, and is then configured according to PMU in every sub-region The planning of quantity, carry out based on maximal tree principle PMU configuration, finally PMU configuration reach completely considerable after, to vulnerability unit Part carries out PMU during N-1 fault and checks and install design additional.

The collocation method of above-mentioned power system phasor measurement unit, it comprises the following steps：

A. using entropy theory, the vulnerability inder of node each in electrical network is ranked up, and the size according to vulnerability inder Each node is divided into severe fragility node, moderate fragility node and strong node three class successively,；

B. configure the planning of quantity according to PMU in every sub-region, carry out the PMU configuration based on maximal tree principle, concrete step Suddenly as follows：

1. configure PMU on the maximum node of vulnerability inder, and set up maximal tree；

For the node of a configured PMU, it is set up and need to meet following three points during maximal tree：

1) all Nodes communicating therewith PMU configuration node periphery are known node；

2) if a no injection node is connected with PMU configuration node, expansible one is no injected node with this and is connected Node as known node；

3) if one is no injected a node node adjacent with a PMU configuration node, expansible this no injects node conduct Known node；

All known node being interconnected constitute a maximal tree, and the connection branch road between node is branch, a maximum All nodes on tree and branch road information all understand；

2. according to maximal tree configuration rule, find next PMU configuration node

When next node is carried out with PMU configuration, following 4 points of maximal tree configuration rules should be met：

1) all nodes on a maximal tree all need not configure PMU；

2) preferentially high to vulnerability inder node carries out PMU configuration；

3) if the vulnerability ranking of two nodes meeting PMU configuration condition is identical in region, preferential configuration connection branch road Many nodes；

4) if the vulnerability ranking of two nodes is identical and connection circuitry number amount is equal in region, preferentially configure apart from former PMU The nearest node of configuring area；

3. judging whether PMU configuration meets the whole network considerable, if meeting, entering step c, if being unsatisfactory for, entering step 4.；

4. judging whether PMU configuration meets interim configuration quantity, if meeting, entering step 5.；If being unsatisfactory for, return step Suddenly 2.

5. the information of minute book stage all PMU configuration node, is that next stage PMU configuration is prepared；

C. PMU configuration reach completely considerable after, vulnerability element is carried out during N-1 fault with PMU and checks and install design additional.

The collocation method of above-mentioned power system phasor measurement unit, is referred to the vulnerability of node each in electrical network using entropy theory Marking the method being ranked up and classifying is：

1. ask node a after being disturbed, to lead to the power flow increment that circuit k causes, constitute power flow increment matrix：

ΔE_ka=P_ka-P_k0

Wherein, P_k0Trend for system branch road k in normal conditions；P_kaIt is to be when node a load increases a unit When system is subject to unit disturbance impact, the trend of branch road k；

2. ask the impact to system for the node a, i.e. the summation of the power flow increment that each node disturbance causes, constitute system shock to Amount：

${\mathrm{\ΔE}}_a=\underset{k=1}{\overset{S}{\Σ}}(P_{ka}-P_{k0})$

In formula, S is system branch number；

3. define the trend entropy of node a：

$H_D\left(a\right)=-\underset{k=1}{\overset{S}{\Σ}}{\mathrm{\η}}_{ka}{\mathrm{ln\η}}_{ka}$

Wherein, η_ka=Δ E_ka/ΔE_aTrend impingement rate for branch road k, the node a that expression branch road k undertakes is to system shock Ratio；

4. obtain the vulnerability inder V of each node_a, and be ranked up from big to small according to index：

$V_a=\frac{{\mathrm{\ΔE}}_a}{H_D\left(a\right)}$

5. according to vulnerability inder V_aAll nodes are divided into 3 classes：Severe fragility node (node vulnerability inder V_a≥ 0.5), moderate fragility node (node vulnerability inder 0.5 ＞ V_a>=0.1) and strong node (node vulnerability inder V_a＜ 0.1).

The collocation method of above-mentioned power system phasor measurement unit, vulnerability element is carried out during N-1 fault PMU check and The method installing design additional is：

1. carry out the ornamental verification under the conditions of N-1, it is to avoid the repeated and redundant of PMU is installed；

With P_i ¹Represent only have, with node i, the set of node that 1 circuit is connected, with P_i ²Represent and at least 2 circuits of node i Connected set of node.Then, according to the definition that individual node is considerable, node ornamental under the conditions of N-1 to be met is it is necessary at least Meet one of following 3 kinds of situations：

1) point i is configured with PMU；

2)P_i ¹In have 1 node to be configured with PMU；

3)P_i ²In have 2 nodes to be configured with PMU.

For the node meeting above-mentioned 3 kinds of situations, at once ensure still not lose ornamental under the conditions of N-1, PMU need not be carried out Repeat install.

If 2. the node i in vulnerability region is unsatisfactory for above-mentioned ornamental verification, PMU is carried out to it and installs additional.

The collocation method of above-mentioned power system phasor measurement unit, for rationally utilizing the PMU configuration under normal operating condition, Three below requirement is proposed to installing additional of PMU：

1) ifRequire to install PMU additional so that i ∈ P in node i₀；

2) if for wantonly two node m ∈ P_i ²,n∈P_i ²All haveRequire to install PMU additional so that i ∈ in node i P₀；

3) if for m ∈ P_i ²There is m ∈ P₀, and for arbitraryHaveThen in the section connecting with node i Install PMU additional on point, that is, be required to meet for a certainMake k ∈ P₀.

The present invention is optimized configuration using maximum tree theory to PMU, and the method can be solved with quick obtaining globally optimal solution Determined unobservable under the conditions of configure under PMU and N-1 fault the difficult problem simultaneously ensureing configuration ornamental and economy stage by stage.Should Method not only achieves preferable balance in terms of economy, safety and Saving in time costs, and fully takes into account existing electrical network In assembled the subregion situation of PMU, motility is good, and exploitativeness is high.

Brief description

The invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 be PMU configuration node periphery maximal tree set up figure (in figure,It is configured with the node of PMU；●：Known to voltage Node；Do not configure the no injection node of PMU；Ordinary node；Circuit known to trend；Trend is unknown Circuit)；

Fig. 2 is the program flow diagram of the present invention.

In literary composition, each symbol inventory is：D_kaFor trend distribution factor on branch road k for the node a；x_cdReactance for branch road k； X_da,X_caFor the corresponding element in the nodal impedance matrix of electrical network under normal circumstances；N is system node number；S is system branch number； ΔE_kaFor node a, the trend of branch road k is impacted；ΔE_aFor the impact to system for the node a；H_DA () is the trend entropy of node a；η_ka Trend impingement rate for branch road k；V_aVulnerability inder for node；P₀For being assembled with the set of node of PMU；P₁Unassembled for itself PMU simultaneously only has the set of node of a connection branch road；P₂For itself unassembled PMU and have more than two connection branch roads sets of node； P_i ¹It is to only have, with node i, the set of node that 1 circuit is connected；P_i ²It is and the node i set of node that at least 2 circuits are connected.

Specific embodiment

The present invention comprises the following steps：

(1) according to entropy theory, the vulnerability inder of node each in electrical network is ranked up, and according to index size by each section Point is divided into severe fragility node, moderate fragility node and strong node three class successively, is PMU inspection during N-1 fault in step c Look into and install additional and prepare.

The present invention is produced to system capacity changes in distribution after certain node is disturbed using DC power flow algorithm prediction Impact, i.e. the vulnerability inder of node, its step is as follows：

1. define trend distribution factor D on branch road k for the node a_kaFor：

$D_{ka}=\frac{X_{da}-X_{ca}}{x_{cd}}---\left(1\right)$

Wherein,

x_cdThe reactance of branch road k；

X_da,X_caCorresponding element in the nodal impedance matrix of electrical network under normal circumstances.

D_kaConstitute N × S rank node trend distribution factor transfer matrix D, N is system node number, S is system branch number.Square For 0 or element representation a certain node disturbance not the applying impact or being conducive to this branch road stable to this branch road for bearing in battle array D Run, therefore hardly system safety operation is impacted, for avoiding, in following calculating, infinitely-great impact occurs, this A little elements can be replaced with a minimum positive number.

2. obtain node to be subject to impact vector to the trend of system during unit disturbance.

Hypothesis system is in balance ground state in normal conditions, and now the trend of branch road k is P_k0；When node a is subject to unit During load disturbance, i.e. Δ P_aThe trend of=1, branch road k is P_ka, the power flow increment that node a causes after being disturbed is

ΔE_ka=P_ka-P_k0=Δ P_aD_ka=D_ka(2)

By Δ E_kaIt is defined as node a the trend of branch road k is impacted, then node a to the impact of system is：

${\mathrm{\ΔE}}_a=\underset{k=1}{\overset{S}{\Σ}}{\mathrm{\ΔE}}_{ka}=\underset{k=1}{\overset{S}{\Σ}}{D}_{ka}---\left(3\right)$

ΔE_aConstitute N-dimensional trend impact vector, show that each node is subject to size during unit disturbance to system loading disturbance.

3. the trend entropy of definition node a is：

$H_D\left(a\right)=-\underset{k=1}{\overset{S}{\Σ}}{\mathrm{\η}}_{ka}{\mathrm{ln\η}}_{ka}---\left(4\right)$

Wherein, η_ka=Δ E_ka/ΔE_aRepresent the trend impingement rate of branch road k.

4. obtain the vulnerability inder of each node, and be ranked up from big to small according to it.

Wherein, the vulnerability inder of node is：

$V_a=\frac{{\mathrm{\ΔE}}_a}{H_D\left(a\right)}---\left(5\right)$

5. all nodes are divided into 3 classes：Severe fragility node (node vulnerability inder V_a>=0.5), moderate fragility node (node vulnerability inder 0.5 ＞ V_a>=0.1) and strong node (node vulnerability inder V_a＜ 0.1).

(2) size according to each node vulnerability inder, carries out PMU configuration stage by stage using maximum tree theory.

The concept of maximal tree：If G=(V, E) is connected graph, T is the spanning tree of G, represents the branch collection of T with E (T), with e (T) Represent the quantity of branch in E (T), represent the collection of the Spanning Trees of G with T (G).If one and only one T^*∈ T (G), to any T ∈ T (G), have e (T^*) ＜ e (T), then claim T^*Maximum (generation) tree for G.

The method of maximal tree is introduced electrical network it is simply that analysis to the electrical network tree generating after local configuration PMU, it is right to deepen The understanding of optimizing rule and operation, carry out distributing rationally of PMU.

(3) PMU configuration reach completely considerable after, vulnerability element is carried out during N-1 fault with PMU check and install additional setting Meter；

Obtain after severe fragility node, moderate fragility node and strong node three class node according to above-mentioned steps, in electrical network In running, severe fragility node accident risk highest, moderate fragility node takes second place, and strong node almost seldom occurs thing Therefore.Therefore, emphasis considers that the PMU carrying out at fragile node under N-1 accident checks and installs additional, can ensure power grid security prison Strengthen its economy on the basis of survey., according to the assessment to economic power system and safety, prioritizing selection is crisp to severe for the present invention Weak bus carry out PMU configuration verification and install additional, secondly, consider further that alignment degree fragility node carries out PMU and installs additional.

Vulnerability element is carried out with PMU during N-1 fault check and install design additional：

1. carry out the ornamental verification under the conditions of N-1, it is to avoid the repeated and redundant of PMU is installed；

Ornamental based on N-1 condition judges as follows：

1) if node i ∈ P₀, according to condition 1, PMU need not be installed additional；

2) if node i ∈ P₁, according to condition 2, ifThen meet considerable under N-1；

3) if node i ∈ P₂, according to condition 3, if there are two node m ∈ P_i ²,n∈P_i ²And have m ∈ P₀,n∈P₀, then meet Considerable under N-1.

Wherein, P₀Represent the set of node being assembled with PMU；P₁Represent itself unassembled PMU and only have the section of a connection branch road Point set；P₂Represent itself unassembled PMU and have the set of node of more than two connection branch roads；P_i ¹Represent only have 1 circuit with node i Connected set of node, P_i ²Represent and the node i set of node that at least 2 circuits are connected.

If 2. the node i in vulnerability region is unsatisfactory for above-mentioned ornamental and judges to install additional it is necessary to carry out PMU.For rationally profit With the PMU configuration under normal operating condition, now PMU is installed additional and propose three below design：

1) ifRequire to install PMU additional so that i ∈ P in node i₀；

2) if for wantonly two node m ∈ P_i ²,n∈P_i ²All haveRequire to install PMU additional so that i ∈ in node i P₀；

3) if for m ∈ P_i ²There is m ∈ P₀, and for arbitraryHaveRequire in connecting with node i PMU is installed additional on node, that is, is required to meet for a certainMake k ∈ P₀.

Below in conjunction with the accompanying drawings, describe the concrete operation step of the present invention in detail.

The first step, is ranked up to the vulnerability inder of node each in electrical network, and according to index size, each node is carried out Classification；Second step, configures the planning of quantity according to PMU in every sub-region, carries out the PMU configuration based on maximal tree principle；3rd Step, PMU configuration reach completely considerable after, vulnerability element is carried out during N-1 fault with PMU and checks and install design additional.

Wherein, when system is completely considerable, the step of the allocation plan of PMU stage by stage based on maximum tree theory includes：

1. configure PMU at vulnerability inder highest node, and set up maximal tree.

For the node of a configured PMU, it is set up and need to meet following three points during maximal tree：

1) all Nodes communicating therewith PMU configuration node periphery are known node；

2) if a no injection node is connected with PMU configuration node, expansible one is no injected node with this and is connected Node as known node；

3) if one is no injected a node node adjacent with a PMU configuration node, expansible this no injects node conduct Known node.

All known node being interconnected constitute a maximal tree, and the connection branch road between node is branch, a maximum All nodes on tree and branch road information all understand.

2. according to maximal tree configuration rule, find next PMU configuration node.

When next node is carried out with PMU configuration, following 4 points of maximal tree configuration rules should be met：

1) all nodes on a maximal tree all need not configure PMU；

2) the preferential node to vulnerability ranking carries out PMU configuration；

3) if the vulnerability ranking of two nodes meeting PMU configuration condition is identical in region, preferential configuration connection branch road Many nodes；

4) if the vulnerability ranking of two nodes is identical and connection circuitry number amount is equal in region, preferentially configure apart from former PMU The nearest node of configuring area.

The PMU configuration to individual node for first of maximal tree configuration rule is optimized, and latter three is to the whole network section The PMU configuration sequence of point proposes requirement, and the first rule has precedence over latter three and judged.

3. judging whether PMU configuration meets the whole network considerable, if meeting, entering the 3rd step, vulnerability element is carried out with N-1 therefore During barrier, PMU checks and installs design additional；If being unsatisfactory for, enter step 4..

4. judging whether PMU configuration meets interim configuration quantity, if meeting, entering step 5.；If being unsatisfactory for, return step Suddenly 2.

5. the information of minute book stage all PMU configuration node, is that next stage PMU configuration is prepared.

Claims (2)

1. a kind of collocation method of power system phasor measurement unit, is characterized in that, methods described is first to node each in electrical network Vulnerability inder be ranked up, and according to the size of vulnerability inder, each node is classified, then according to every sub-region Interior PMU configures the planning of quantity, carries out the PMU configuration based on maximal tree principle, finally PMU configuration reach completely considerable after, Vulnerability element is carried out with PMU during N-1 fault check and install design additional；

Configuration is carried out according to the following steps：

A. using entropy theory, the vulnerability inder of node each in electrical network is ranked up, and the size according to vulnerability inder will be each Node is divided into severe fragility node, moderate fragility node and strong node three class successively；

Impact after certain node is disturbed, system capacity changes in distribution being produced using DC power flow algorithm prediction, i.e. node Vulnerability inder, step is as follows：

1., define trend distribution factor D on branch road k for the node a_kaFor：

Wherein,

x_cdThe reactance of branch road k；

X_da,X_caCorresponding element in the nodal impedance matrix of electrical network under normal circumstances；

D_kaConstitute N × S rank node trend distribution factor transfer matrix D, N is system node number, S is system branch number；In matrix D For 0 or for negative element representation a certain node disturbance not applying to impact or be conducive to this branch road stable operation to this branch road, Impact thus without to system safety operation, for avoiding infinitely-great impact in following calculating, these elements can Replaced with a minimum positive number；

2., obtain node to be subject to impact vector to the trend of system during unit disturbance；

Hypothesis system is in balance ground state in normal conditions, and now the trend of branch road k is P_k0；When node a is subject to specific load During disturbance, i.e. Δ P_aThe trend of=1, branch road k is P_ka, the power flow increment that node a causes after being disturbed is

ΔE_ka=P_ka-P_k0=Δ P_aD_ka=D_ka(2)

By Δ E_kaIt is defined as node a the trend of branch road k is impacted, then node a to the impact of system is：

ΔE_aConstitute N-dimensional trend impact vector, show that each node is subject to size during unit disturbance to system loading disturbance, in formula, S is system branch number；

3., the trend entropy of definition node a is：

Wherein, η_ka=Δ E_ka/ΔE_aRepresent the trend impingement rate of branch road k；

4., obtain the vulnerability inder of each node, and be ranked up from big to small according to it；

Wherein, the vulnerability inder of node is：

5., all nodes are divided into 3 classes：Severe fragility node, its node vulnerability inder V_a>=0.5, moderate fragility node, its Node vulnerability inder 0.5 ＞ V_a>=0.1 and strong node, its node vulnerability inder V_a＜ 0.1；

B. configure the planning of quantity according to PMU in every sub-region, carry out the PMU configuration based on maximal tree principle, concrete steps are such as Under：

1. configure PMU on the maximum node of vulnerability inder, and set up maximal tree

For the node of a configured PMU, it is set up and need to meet following three points during maximal tree：

1) all Nodes communicating therewith PMU configuration node periphery are known node；

2) if a no injection node is connected with PMU configuration node, expansible one is no injected the section that node is connected with this Point is as known node；

3) if one is no injected a node node adjacent with a PMU configuration node, expansible this no injects node as known Node；

2. according to maximal tree configuration rule, find next PMU configuration node

When next node is carried out with PMU configuration, following 6 points of maximal tree configuration rules should be met：

1) node being connected with PMU configuration node all need not configure PMU；

2) if a no injection node is connected with PMU configuration node, no inject a certain node that node is connected no with this PMU need to be configured；

3) if a no injection node is interconnected by a node with PMU configuration node, this no injects node and need not configure PMU；

4) configure PMU on the preferential node maximum in vulnerability inder；

5) if the vulnerability ranking of two nodes meeting PMU configuration condition is identical in region, more than preferential configuration connection branch road Node；

6) if the vulnerability ranking of two nodes is identical and connection circuitry number amount is equal in region, preferential configuration is apart from former PMU configuration The nearest node in region；

3. judging whether PMU configuration meets the whole network considerable, if meeting, entering step c, if being unsatisfactory for, entering step 4.；

4. judging whether PMU configuration meets interim configuration quantity, if meeting, entering step 5.；If being unsatisfactory for, return to step is 2.

5. the information of minute book stage all PMU configuration node, is that next stage PMU configuration is prepared；

C. PMU configuration reach completely considerable after, vulnerability element is carried out during N-1 fault with PMU and checks and install design additional；

Vulnerability element is carried out with the method that during N-1 fault, PMU checked and installed additional design is：

1. carry out the ornamental verification under the conditions of N-1；

With P_i ¹Represent only have, with node i, the set of node that 1 circuit is connected, with P_i ²Expression is connected with least 2 circuits of node i Set of node；Then, according to the definition that individual node is considerable, node ornamental under the conditions of N-1 to be met it is necessary at least meet with One of lower 3 kinds of situations：

1) node i is configured with PMU；

2)P_i ¹In have 1 node to be configured with PMU；

3)P_i ²In have 2 nodes to be configured with PMU；

For the node meeting above-mentioned 3 kinds of situations, you can ensure still not losing ornamental under the conditions of N-1, the weight of PMU need not be carried out Multiple installation；

If 2. the node i in vulnerability region is unsatisfactory for above-mentioned ornamental verification, PMU is carried out to it and installs additional.

2. the collocation method of power system phasor measurement unit according to claim 1, is characterized in that, during PMU configuration, right The three below that adds of PMU requires：

1) ifRequire to install PMU additional so that i ∈ P in node i₀；

2) if for wantonly two node m ∈ P_i ²,n∈P_i ²All haveRequire to install PMU additional so that i ∈ P in node i₀；Its In, P₀For being assembled with the set of node of PMU, k is the code name of branch road；

3) if for m ∈ P_i ²There is m ∈ P₀, and for arbitraryHaveThen add on the node connecting with node i Dress PMU, that is, be required to meet for a certainMake k ∈ P₀.