CN105791280A - Method for defending data integrity attack in direct state estimation of power system - Google Patents

Abstract

The invention discloses a method for defending a data integrity attack in direct state estimation of a power system. The method comprises the following steps: estimating a real-time state of a direct current system by using a weighted least square method; constructing a minimum cost data integrity attack model to simulate the behavior of an attacker; resolving the minimum cost data integrity attack by using an algorithm based on linear transformation to obtain an optimal attack vector at the moment; if the current optimal attack vector is obtained, realizing a PMU optimized configuration defense strategy based on a greedy algorithm, and after the configuration is completed, the occurrence of the data integrity attack is prevented from the source, and meanwhile, the complete observability of the system is guaranteed. By adopting the method disclosed by the invention, the data integrity attack in the direct state estimation of the power system can be accurately and quickly defended, and the accuracy and security of the state estimation of the power system are improved.

Description

A kind of resist the method that power system DC state estimated median is attacked according to integrity

Technical field

The invention belongs to power system information safety and control technical field, relating to a kind of resisting the method that power system DC state estimated median is attacked according to integrity

Background technology

Along with the realization that construction and the large scale electric network of Large Copacity long distance power transmission system interconnect, the safety and stability problem of modern power systems becomes further to highlight.Data integrity is attacked, namely assailant when there being certain understanding to power system topology, distort the sensor metric data that EMS (EMS) receives, and according to the result of predetermined target change state estimation, finally make EMS utilize the estimated result of mistake to make incorrect electric power adjustment or control decision.

In current power system, the operation of power system itself can be caused safely serious threat by the data integrity attack for EMS, therefore need badly and work out a kind of defence method attacked according to integrity for power system DC state estimated median so that this attack can by faster and more effective discovery resisting.Defence method before this is mostly focused on protects important measurement or isolates, and these defence methods increase the extra cost of system simultaneously.And the PMU of utilization of the present invention distributes the method being on the defensive that data integrity is attacked rationally, ensureing on the basis of system ornamental, do not bring extra cost price to system.

PMU (phasormeasurementunit) Chinese is synchronous phasor measurement unit, is a kind of based on GPS geo-location system, it is possible to the measurement apparatus of new generation to electrical network measurement and monitoring.PMU can measure the voltage phasor of node at the node installed, and the electric current phasor of the associated branch being connected with this node, its communication function having, make it possible to realize connecting between scheduling station, scheduling station also according to the relevant information of each eyeball, can understand the ruuning situation of whole network.Traditional EMS system can not detect the dynamic behaviour of electrical network in real time, and the appearance of PMU then achieves the real-time detection to operation of power networks state, and the safe and stable operation for ensureing power system creates condition.Power system, for measuring and monitor the SCADA system that systematic steady state runs, lays particular emphasis on monitoring systematic steady state operation conditions, and the measurement cycle is second level, and lacks common time labelling accurately between different location.And based on the PMU device that ripe GPS technology, communication technology, DSP technology are developed, possess high stability and reliability, in high precision, powerful computing, storage and ability to communicate, provide possibility for realizing Electrical Power System Dynamic monitoring.

PMU is based on the precision time service function of GPS geo-location system so that all with gps time labelling in its measurement data, therefore it is considered that the measurement obtained by PMU measurements is all safe and very difficult is hacked again.Again due to the high cost of PMU, it is unpractical that each node at the whole network configures PMU, so this allows for us is devoted to find the PMU collocation strategy of a kind of optimum, make power system utilize minimal number of PMU just can successfully resist data integrity to attack, and make system reach complete Observable, but prior art does not occur similar disclosing.

Summary of the invention

It is an object of the invention to the shortcoming overcoming above-mentioned prior art, it is provided that a kind of resist the method that power system DC state estimated median is attacked according to integrity, the method can utilize minimal number of PMU to resist data integrity and attack.

For reaching above-mentioned purpose, of the present invention resist the method that power system DC state estimated median attacks according to integrity and comprise the following steps:

1) network parameter of power system is obtained from EMS；

2) data acquisition and supervisor control receive sensor measurement, then are sent to the state estimator of EMS by sensor measurement, and the state estimator of EMS estimates the real-time status of power system according to sensor measurement；

3) minimum cost data integrity attack model is set up:

$\underset{c}{\min }\left|\right|H^{\stackrel{\‾}{S}}c|{|}_0$

s.t.H^SC=0

||c||_∞≥τ

Wherein, c is side-play amount, and τ is preset value, and S is the safe subset being initialized as sky, and H is the measurement Jacobian matrix of system；

4) according to step 1) network parameter of power system that obtains solves described minimum cost data integrity attack model, obtains minimum cost vector of attack a；

5) the Jacobian matrix H of system is carried out piecemeal, according to the measurement of all the sensors, system Jacobian matrix H is divided into N-1 matrix-block H by row^Li, then find the non-zero amount measurement a in minimum cost vector of attack a_k, wherein, Li=1 ..., N-1, N is the interstitial content of power system, k=1 ..., Nu, Nu=| | a | |₀；

Structure count vector M (Li), wherein, Li=1 ..., N-1, Nu the measurement calculated in minimum cost vector of attack a is included in each matrix-block H^LiIn number, maximum Nu measurement is included in each matrix-block H^LiIn number be denoted as M (Li^*), i.e. Li^*Node is the optimal node of configuration PMU, then PMU is configured to Li^*On node, simultaneously by matrix-block H^Li*Add in safe subset S；

6) repeat step 3), 4) and 5), until Rank (H^STill)=N-1, complete defence data integrity during power system DC state is estimated and attack.

The network parameter of described power system includes the branch road number of transmission line of electricity, first node serial number, end-node numbering, series resistance, series reactance, shunt conductance and shunt susceptance.

Sensor measurement includes the meritorious highway of branch road and node injects active power.

If sensor measurement includes branch road active power and node injects active power z, z=(P₁,P₂,..P_g..,P_N,P_ij,P_ji,...)^T, wherein, P_i,jFor the branch road active power between i-th node to jth node, P_gIt is that the g node injects active power；

Then power system DC state estimated valueFor:

$\hat{x}={\left(H^T{R}^{-1}H\right)}^{-1}{H}^T{R}^{-1}z$

Wherein, R is weight matrix.

The state variable of power system includes node voltage phase angle x, wherein, and x=(θ₂,θ₃,..θ_h..,θ_N)^T, θ_hBe the h node voltage phase angle, then i-th node is to the branch road active-power P between jth node_i,jActive-power P is injected with i-th node_iIt is respectively as follows:

$P_{ij}=\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_j}{X_{ij}}$

Wherein, X_ijFor the branch admittance between i-th node to jth node,For the node set being connected with i-node.

Step 4) concrete operations be:

1a) by step 1) network parameter of power system that obtains obtains the measurement Jacobian matrix H of system, and the measurement Jacobian matrix H of system is carried out transposition and obtains row non-singular matrix H^T；

2a) to row non-singular matrix H^TCarry out Applying Elementary Row Operations, obtain row simplest form matrix；

3a) find a line that in row simplest form matrix, 0 element is maximum, then pass through rank transformation and all neutral elements of this row are exchanged to the most prostatitis of this row；

4a) by step 3a) matrix that obtains obtains row simplest form matrix newly by Applying Elementary Row Operations, then step 3a is repeated), until the position of the minimum a line of nonzero element do not change and in the minimum a line of nonzero element 0 element number constant till, obtain matrix (H^T)″；

5a) selecting step 4a) matrix (H that obtains^T) " in the maximum a line of nonzero element number, then using a line maximum for this nonzero element as minimum cost vector of attack a.

Work as Li^*When node is unique, then select the node that wherein degree of appearance is the highest as the optimal node configuring PMU

The method have the advantages that

Of the present invention resist method that power system DC state estimated median attacks according to integrity when concrete operations, by setting up the complete attack model of minimum cost data, obtain minimum cost vector of attack, the Jacobian matrix of system is carried out piecemeal again, and maximum Nu measurement is included in each matrix-block H^LiIn number be denoted as M (Li^*), i.e. Li^*Node is the optimal node of configuration PMU, then is configured in optimal node to by PMU, it is achieved utilizes minimal number of PMU to resist data integrity and attacks, and realizes blocking data integrity on source simultaneously and attacks, and makes power system obtain Observable.

Accompanying drawing explanation

Fig. 1 is the flow chart of the present invention；

Fig. 2 is the flow chart solving minimum cost data integrity attack model；

Fig. 3 is step 5 in the present invention) flow chart；

Fig. 4 is that the present invention PMU to attacking for data integrity under IEEE30 node system scale defends configuration figure.

Detailed description of the invention

Below in conjunction with accompanying drawing, the present invention is described in further detail:

With reference to Fig. 1, of the present invention resist the method that power system DC state estimated median attacks according to integrity and comprise the following steps:

1) obtain the network parameter of power system from EMS, wherein, the network parameter of described power system includes the branch road number of transmission line of electricity, first node serial number, end-node numbering, series resistance, series reactance, shunt conductance and shunt susceptance.

2) data acquisition receives sensor measurement with supervisor control, again sensor measurement is sent to the state estimator of EMS, the state estimator of EMS estimates the real-time status of power system according to sensor measurement, wherein, sensor measurement includes the meritorious highway of branch road and node injection active power；

If sensor measurement includes branch road active power and node injects active power z, z=(P₁,P₂,..P_g..,P_N,P_ij,P_ji,...)^T, wherein, P_i,jFor the branch road active power between i-th node to jth node, P_gBeing that the g node injects active power, the state variable of power system includes node voltage phase angle x, wherein, and x=(θ₂,θ₃,..θ_h..,θ_N)^T, θ_hIt is the h node voltage phase angle, wherein, the voltage phase angle θ of first node₁Be 0, then i-th node is to the branch road active-power P between jth node_i,jActive-power P is injected with i-th node_iIt is respectively as follows:

$P_{ij}=\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_j}{X_{ij}}$

Wherein, X_ijFor the branch admittance between i-th node to jth node,For the node set being connected with i-node；

Thus can set up inearized model:

Z=Hx+e

Wherein, H is the Jacobi measurement matrix of m row n row, and m > n；

State estimation vectorFor making object functionReach minimum x, then power system DC state estimated valueFor:

$\hat{x}={\left(H^T{R}^{-1}H\right)}^{-1}{H}^T{R}^{-1}z$

Wherein, R is weight matrix.

3) minimum cost data integrity attack model is set up:

$\underset{c}{\min }\left|\right|H^{\stackrel{\‾}{S}}c|{|}_0$

s.t.H^SC=0

||c||_∞≥τ

Wherein, c is side-play amount, and τ is preset value, and S is the safe subset being initialized as sky, and H is the measurement Jacobian matrix of system；

It should be noted that after PMU configuration, the measurement that PMU protects is put in the safe subset S being initialized as sky,It is remaining measurement, obtains security constraint H^SC=0；

4) according to step 1) network parameter of power system that obtains solves described minimum cost data integrity attack model, obtains minimum cost vector of attack a, and the method wherein solved specifically includes following steps:

1a) by step 1) network parameter of power system that obtains obtains the measurement Jacobian matrix H of system, and the measurement Jacobian matrix H of system is carried out transposition and obtains row non-singular matrix H^T；

2a) to row non-singular matrix H^TCarry out Applying Elementary Row Operations, obtain row simplest form matrix；

3a) find a line that in row simplest form matrix, 0 element is maximum, then pass through rank transformation and all neutral elements of this row are exchanged to the most prostatitis of this row；

4a) by step 3a) matrix that obtains obtains row simplest form matrix newly by Applying Elementary Row Operations, then step 3a is repeated), until the position of the minimum a line of nonzero element do not change and in the minimum a line of nonzero element 0 element number constant till, obtain matrix (H^T)″；

5a) selecting step 4a) matrix (H that obtains^T) " in the maximum a line of nonzero element number, then using a line maximum for this nonzero element as minimum cost vector of attack a.

It should be noted that, above-mentioned solution throughway carries out towards optimum direction in the process of the problem of solution always: namely nonzero element number is minimum, until the matrix of final abbreviation does not change, therefore the asymptotic optimality solution of problem can be obtained, can in the hope of assailant's asymptotic optimality vector of attack under consuming minimum cost situation by above solution throughway.

5) the Jacobian matrix H of system is carried out piecemeal, according to the measurement of all the sensors, system Jacobian matrix H is divided into N-1 matrix-block H by row^Li, then find the non-zero amount measurement a in minimum cost vector of attack a_k, wherein, Li=1 ..., N-1, N is the interstitial content of power system, k=1 ..., Nu, Nu=| | a | |₀；

Structure count vector M (Li), wherein, Li=1 ..., N-1, Nu the measurement calculated in minimum cost vector of attack a is included in each matrix-block H^LiIn number, maximum Nu measurement is included in each matrix-block H^LiIn number be denoted as M (Li^*), i.e. Li^*Node is the optimal node of configuration PMU, then PMU is configured to Li^*On node, simultaneously by matrix-block H^Li*Add in safe subset S；Wherein, Li is worked as^*When node is unique, then directly PMU is configured to Li^*On node；Work as Li^*When node is unique, then select the node that wherein degree of appearance is the highest as the optimal node configuring PMU

6) repeat step 3), 4) and 5), until Rank (H^STill)=N-1, complete defence data integrity during power system DC state is estimated and attack.

According to step 6) in PMU distribute strategy rationally, the node tried to achieve is carried out corresponding PMU configuration, after configuration terminates, data integrity is attacked and is become no longer feasible, and system has also reached complete Observable.

With reference to Fig. 4, the PMU being under IEEE30 node scale to attack for data integrity defends profile instance figure, and dotted line represents the corresponding configuration sequence of PMU.Be can be seen that by figure, the configured number of PMU about maintains about 1/3, basically identical with the number only considering system ornamental and configure, illustrating that the present invention is in order to defend data integrity not bring extra cost price to system while attacking, this is also an advantage place of the present invention.

Claims (7)

1. resist the method that power system DC state estimated median is attacked according to integrity for one kind, it is characterised in that comprise the following steps:

1) network parameter of power system is obtained from EMS；

2) data acquisition and supervisor control receive sensor measurement, then are sent to the state estimator of EMS by sensor measurement, and the state estimator of EMS estimates the real-time status of power system according to sensor measurement；

3) minimum cost data integrity attack model is set up:

$\underset{c}{min}\left|\right|H^{\stackrel{\‾}{S}}c|{|}_0$

s.t.H^SC=0

||c||_∞≥τ

Wherein, c is side-play amount, and τ is preset value, and S is the safe subset being initialized as sky, and H is the measurement Jacobian matrix of system；

4) according to step 1) network parameter of power system that obtains solves described minimum cost data integrity attack model, obtains minimum cost vector of attack a；

5) the Jacobian matrix H of system is carried out piecemeal, according to the measurement of all the sensors, system Jacobian matrix H is divided into N-1 matrix-block H by row^Li, then find the non-zero amount measurement a in minimum cost vector of attack a_k, wherein, Li=1 ..., N-1, N is the interstitial content of power system, k=1 ..., Nu, Nu=| | a | |₀；

Structure count vector M (Li), wherein, Li=1 ..., N-1, Nu the measurement calculated in minimum cost vector of attack a is included in each matrix-block H^LiIn number, maximum Nu measurement is included in each matrix-block H^LiIn number be denoted as M (Li^*), i.e. Li^*Node is the optimal node of configuration PMU, then PMU is configured to Li^*On node, simultaneously by matrix-blockAdd in safe subset S；

6) repeat step 3), 4) and 5), until Rank (H^STill)=N-1, complete defence data integrity during power system DC state is estimated and attack.

2. according to claim 1 resist the method that power system DC state estimated median is attacked according to integrity, it is characterized in that, the network parameter of described power system includes the branch road number of transmission line of electricity, first node serial number, end-node numbering, series resistance, series reactance, shunt conductance and shunt susceptance.

3. according to claim 1 resist the method that power system DC state estimated median is attacked according to integrity, it is characterised in that sensor measurement includes the meritorious highway of branch road and node injects active power.

4. according to claim 1 resist the method that power system DC state estimated median is attacked according to integrity, it is characterised in that set sensor measurement and include branch road active power and node injects active power z, z=(P₁,P₂,..P_g..,P_N,P_ij,P_ji,...)^T, wherein, P_i,jFor the branch road active power between i-th node to jth node, P_gIt is that the g node injects active power；

Then power system DC state estimated valueFor:

$\hat{x}={\left(H^T{R}^{-1}H\right)}^{-1}{H}^T{R}^{-1}z$

Wherein, R is weight matrix.

5. according to claim 3 resist the method that power system DC state estimated median is attacked according to integrity, it is characterised in that the state variable of power system includes node voltage phase angle x, wherein, x=(θ₂,θ₃,..θ_h..,θ_N)^T, θ_hBe the h node voltage phase angle, then i-th node is to the branch road active-power P between jth node_i,jActive-power P is injected with i-th node_iIt is respectively as follows:

$P_{ij}=\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_j}{X_{ij}}$

Wherein, X_ijFor the branch admittance between i-th node to jth node,For the node set being connected with i-node.

6. according to claim 1 resist the method that power system DC state estimated median is attacked according to integrity, it is characterised in that step 4) concrete operations be:

1a) by step 1) network parameter of power system that obtains obtains the measurement Jacobian matrix H of system, and the measurement Jacobian matrix H of system is carried out transposition and obtains row non-singular matrix H^T；

2a) to row non-singular matrix H^TCarry out Applying Elementary Row Operations, obtain row simplest form matrix；

3a) find a line that in row simplest form matrix, 0 element is maximum, then pass through rank transformation and all neutral elements of this row are exchanged to the most prostatitis of this row；

4a) by step 3a) matrix that obtains obtains row simplest form matrix newly by Applying Elementary Row Operations, then step 3a is repeated), until the position of the minimum a line of nonzero element do not change and in the minimum a line of nonzero element 0 element number constant till, obtain matrix (H^T)″；

5a) selecting step 4a) matrix (H that obtains^T) " in the maximum a line of nonzero element number, then using a line maximum for this nonzero element as minimum cost vector of attack a.

7. according to claim 1 resist the method that power system DC state estimated median is attacked according to integrity, it is characterised in that work as Li^*When node is unique, then select the node that wherein degree of appearance is the highest as the optimal node configuring PMU.