CN107611965B - UPFC-containing power system economic and static safety comprehensive optimization method - Google Patents
UPFC-containing power system economic and static safety comprehensive optimization method Download PDFInfo
- Publication number
- CN107611965B CN107611965B CN201710834915.6A CN201710834915A CN107611965B CN 107611965 B CN107611965 B CN 107611965B CN 201710834915 A CN201710834915 A CN 201710834915A CN 107611965 B CN107611965 B CN 107611965B
- Authority
- CN
- China
- Prior art keywords
- upfc
- line
- power
- static safety
- bus
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 230000003068 static effect Effects 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 40
- 238000005457 optimization Methods 0.000 title claims abstract description 34
- 239000002245 particle Substances 0.000 claims abstract description 42
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 11
- 238000004364 calculation method Methods 0.000 claims abstract description 11
- 238000011156 evaluation Methods 0.000 claims description 20
- 238000012163 sequencing technique Methods 0.000 claims description 10
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000010206 sensitivity analysis Methods 0.000 claims description 6
- 239000000243 solution Substances 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000003990 capacitor Substances 0.000 claims description 3
- 238000012795 verification Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 6
- 238000010586 diagram Methods 0.000 description 12
- 238000011160 research Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010587 phase diagram Methods 0.000 description 1
Images
Landscapes
- Supply And Distribution Of Alternating Current (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
The invention discloses a comprehensive optimization method for economy and static safety of a power system containing a UPFC. Because the system safety is prior to the system operation economy, the optimization process in the invention is divided into an inner layer and an outer layer, the outer layer takes the system operation cost as a target function, the inner layer takes the system static safety index as the target function, and the inner layer and the outer layer are connected in a mode of adding punishment items. The invention considers the static safety constraint of the system N-1, and because the UPFC has a plurality of tide control modes, and different control modes have different responses when the system has a safety fault, the invention enables the selection of the UPFC control mode to be in the whole optimization process. And solving by adopting a particle swarm algorithm, calculating inner layer objective function values of the UPFC in different control modes for each generation of individuals, and selecting the optimal control parameters and control modes of the UPFC, wherein the calculation results show that the method can obviously improve the running economy and static safety of the system.
Description
Technical Field
The invention relates to the field of power system safety and control, in particular to a comprehensive optimization method for economy and static safety of a power system containing a UPFC.
Background
With the development of Flexible Alternating Current Transmission System (FACTS) technology, more and more power electronic power transmission equipment is applied to a power system, and the power transmission mode of the traditional power system is changed silently. The Unified Power Flow Controller (UPFC) is a typical representative of FACTS equipment, has the capabilities of controlling line power flow, stabilizing bus voltage and improving system stability, has strong functions, and provides a new control and regulation means for the operation of a power system. Meanwhile, along with the continuous development of the power system, the economy and the safety of the power system are more and more important, and in order to more reasonably utilize the existing power transmission and distribution equipment and fully exert the control capability of the UPFC, research needs to be carried out on an economic and safety comprehensive optimization method of the power system containing the UPFC.
After a UPFC load flow calculation model is established by a power injection method, three control parameters of the UPFC are as follows: the parallel side injection current is mainly used for stabilizing the exchange of active power between the parallel side bus voltage and the series-parallel side, and the amplitude and the phase angle of the series side equivalent voltage source are used for controlling the line power flow. Therefore, the access of the UPFC not only brings new control parameters to the system power flow optimization model, but also increases constraint conditions, and can improve the complexity of power flow optimization.
In addition, for the power system including the UPFC, when the UPFC performs power flow control, the control target may be line power flow, bus voltage and phase angle thereof, and line impedance. According to different control targets of the UPFC, the UPFC has four different control modes, which are respectively: constant power control, phase angle regulation control, impedance compensation control, and voltage regulation control. Considering that the UPFC has different control characteristics of power flow in different control modes, the influence of the UPFC on the power flow of the system depends on the control mode, particularly in the case of a safety failure of the system. Therefore, the UPFC control mode has an influence on the safety of the system, the research on the existing UPFC optimization aspect generally researches the fixed power control mode based on the UPFC, only optimizes the control target and the control parameter of the UPFC in the fixed power mode, and does not consider the situations of the other three control modes.
The economy and the safety of the power system have certain contradiction, a reasonable and effective optimization strategy is very important, and the method provides the UPFC power system optimization method considering the economy and the safety of the power system comprehensively.
Disclosure of Invention
In order to solve the existing problems, the invention provides a load flow calculation method considering a UPFC control mode, because the safety of a power system is prior to the economy, the optimization process is divided into an inner layer and an outer layer for processing, the static safety of the system is optimized at the inner layer, the running economy of the system is optimized at the outer layer, and the economy is restrained by the safety. The inner layer establishes a static safety evaluation index as a target function, and simultaneously considers the selection of four control modes of the UPFC; and the outer layer adopts the system operating cost and the penalty term generated by the inner layer objective function as the objective function. The invention provides a comprehensive optimization method for economy and static safety of a power system with UPFC (unified power flow controller), which adopts a particle swarm algorithm to solve, and comprises the following steps:
(1) reading system network data, generator output and load size related data;
(2) setting the size of the population,The PSO algorithm basic information related to the maximum iteration number and the maximum particle velocity value initializes the position and the velocity of each particle, wherein the position information of the particle comprises three control variables of a traditional control parameter and a UPFC, namely [ V ]gen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk]；
(3) Calculating system power flow under a corresponding operation mode of each particle, calculating system operation cost, namely an outer layer objective function value and a control target under each control mode of the UPFC, and recording whether an overload condition exists or not;
(4) and (3) calculating the load flow of each broken line of each line by a sensitivity analysis method for the particles without overload conditions, further calculating an evaluation index PI, and sequencing the faults.
(5) The N-1 static security checks are performed in the order in the expected failure set. Respectively calculating inner layer objective function values after N-1 faults under four control modes until a system does not have a line overload phenomenon after a certain fault, and comparing the advantages and disadvantages of the control modes by taking the maximum value of the objective function under each fault which is calculated;
(6) the particles are evaluated according to the principle that the safety of the system is prior to the economy, and the comparison between the particles and the particles is included. Firstly, comparing whether the particles are overloaded in a normal state or not, secondly, comparing the overload condition of the system after N-1, thirdly, comparing the balance degree of the flow distribution of the system, lastly, comparing the economic indexes of the particles, updating the individual optimal pbest data of each particle according to the comparison result, and replacing the original data in the global optimal gbest with the optimal solution in the pbest, wherein the pbest and the gbest comprise traditional control variables, UPFC control parameters and control modes thereof;
(7) updating the position and the velocity vector of each particle through a particle swarm algorithm;
(8) checking whether the maximum iteration times are reached, if not, turning to the step (5), otherwise, turning to the step (9);
(9) and outputting the final UPFC control parameter and the optimization result of the control mode.
Further, the model in the second step is optimized;
where the variables are optimized as:
[Vgen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk] (2)；
in the formula, Vgen、PgenFor generator terminal voltage and active power, T is the OLTC tap position, C is the capacitance of the parallel compensation capacitor, Vse,θse,VkIs a control variable of the UPFC.
Further, performing equality constraint on the model in the second step;
for an uninstalled UPFC node, the following flow balance is satisfied:
where i is 1,2 … N, and does not include nodes at both ends of UPFC, k ∈ i denotes a generator connected to the bus i, and P represents a node at both ends of UPFCGFor active power output of the generator, PLi、QLiAs a load on the bus i, Gij、BijFor conductance and susceptance, theta, on the lines i-jijIs the phase angle difference between two ends of the line i-j, i.e. thetaij＝θi-θj；
For the UPFC installed bus, the bus connecting with the UPFC is recorded as s and r, and the power balance equation of the bus s and r is as follows:
in the formula, Ps(upfc)、Qs(upfc)Injected power, P, for UPFC to bus sr(upfc)、Qr(upfc)The injection power of the UPFC to the bus r;
since the UPFC itself cannot generate active power, there are internal constraints on the UPFC itself:
Psh+Pse＝0 (5)。
further, performing inequality constraint on the model in the second step;
constraint of control variables:
and (3) state variable constraint:
the method comprises the following steps of limiting the voltage of a load node bus and limiting the reactive power output of a generator:
Vmin≤V≤Vmax (7)；
QGmin≤QG≤QGmax (8)。
further, under the condition of normal operation, the three-level evaluation indexes of the total number of the system out-of-limit lines, the total number of the system out-of-limit lines under the N-1 state and the static safety margin of the system form a static safety evaluation function of the system;
setting the total number of the overload lines as f under the normal condition of the system1(x) The total number of the overload lines in the N-1 state of the system is f2(x) System static safety margin f3(x) Suppose that the system has n lines, the bus has k lines, and the load factor of the ith line is lambdaiThe voltage of the ith bus is ViThe upper and lower limits of the bus voltage are Vi min，Vi maxThe power generator has m generators, and the output of the ith generator is Pi+jQiThe upper and lower limits are
The distance from the system operating point Q to the static safety limit LM of the line is dlineThe safety margin of the bus voltage is dbusDefining the system static safety margin as follows:
f3(x)＝1/dline+dgen+dbus (9)；
wherein,
further, the operating economy of the power system is measured by adopting an operating cost index P (x) of the power system, the form of adding a penalty item and the system safety are adopted, the safety of the system is measured by using the above three-level evaluation index, when the system is out of limit under normal conditions, the solution is given up, when the power flow of the system is out of limit after N-1, the economic index is punished correspondingly, and meanwhile, in order to enable the static safety margin of the system to be as high as possible, the static safety margin index of the system is added into an objective function, so that the following objective function is formed:
and (3) comprehensive optimization target:
f(x)＝[N2(x)r+P(x)]f3(x) (13)；
wherein P (x) is the system operating cost, f3(x) To be aInverse of static safety margin, N2(x) Maximum number of line overload after N-1 of the system, r is penalty coefficient, PlossIs the system loss.
Further, the static safety fault sequencing method adopted in the fifth step is as follows:
establishing the following scalar function PI to comprehensively reflect the overload condition of the system:
in the formula: piFor active power on line i, PicFor transmission capacity limits, alpha, on line iiNumber of parallel paths, ω, in line iiNL is the total number of system branches to reflect the weight coefficient of the importance of the line i;
when the system is not under an overload condition,
the PI indexes are not more than 1 and are small; when there is line overload in the system, the line is overloaded
If the square function is larger than 1, the PI index becomes very large, so that the index can reflect the static safety of the system;
when the kth line is disconnected, the power flow P on the ith line is calculated by the sensitivity analysis methodi', i ═ 1,2, … NL and i ≠ k, which is an evaluation function of:
before and after the line is broken, the evaluation index variation is as follows:
ΔPIk＝PI′-PI (18)；
and performing disconnection calculation on all lines in the system, and sequencing the obtained delta PI, wherein the sequence is the sequence of each fault in the expected fault set.
The invention discloses a comprehensive optimization method for economy and static safety of a power system containing UPFC (unified power flow controller). As the system safety is prior to the system operation economy, the optimization process in the invention is divided into an inner layer and an outer layer, wherein the outer layer takes the system operation cost as a target function, the inner layer takes a system static safety index as a target function, and the inner layer and the outer layer are connected by adding a punishment item. The invention considers the static safety constraint of the system N-1, and because the UPFC has a plurality of tide control modes, and different control modes have different responses when the system has a safety fault, the invention enables the selection of the UPFC control mode to be in the whole optimization process. And solving by adopting a particle swarm algorithm, calculating inner layer objective function values of the UPFC in different control modes for each generation of individuals, and selecting the optimal control parameters and control modes of the UPFC, wherein the calculation results show that the method can obviously improve the running economy and static safety of the system.
Drawings
FIG. 1 is a flow chart of a UPFC power system economic and static safety comprehensive optimization method;
FIG. 2 is a wiring diagram of a test system;
FIG. 3 is a diagram of a UPFC power injection model;
FIG. 4 is a schematic diagram of a UPFC configuration;
FIG. 5 is an iterative convergence diagram;
FIG. 6 is a UPFC series side equivalent circuit diagram;
FIG. 7 is a UPFC voltage control mode phasor diagram;
FIG. 8 is a phase diagram of a UPFC phase angle control mode;
FIG. 9 is a UPFC impedance compensation control mode phasor diagram;
fig. 10 is a phasor diagram of a UPFC constant power control mode.
Detailed Description
The invention is described in further detail below with reference to the following detailed description and accompanying drawings:
the invention provides a load flow calculation method considering a UPFC control mode, because the safety of a power system is prior to the economy, the optimization process is divided into an inner layer and an outer layer for processing, the static safety of the system is optimized on the inner layer, the running economy of the system is optimized on the outer layer, and the economy is restrained by the safety. The inner layer establishes a static safety evaluation index as a target function, and simultaneously considers the selection of four control modes of the UPFC; and the outer layer adopts the system operating cost and the penalty term generated by the inner layer objective function as the objective function. And solving by adopting a particle swarm algorithm.
The invention provides a load flow calculation method considering a UPFC control mode as shown in figure 1, which comprises the following specific steps:
(1) reading system network data, generator output and load size related data;
(2) setting PSO algorithm basic information related to the population size, the maximum iteration number and the maximum particle velocity value, and initializing the position and the velocity of each particle, wherein the position information of the particle comprises three control variables, namely [ V ] and UPFCgen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk]；
(3) Calculating system power flow under a corresponding operation mode of each particle, calculating system operation cost (outer layer objective function value) and a control target under each control mode of the UPFC, and recording whether an overload condition exists or not;
(4) and (3) calculating the load flow of each broken line of each line by a sensitivity analysis method for the particles without overload conditions, further calculating an evaluation index PI, and sequencing the faults.
(5) The N-1 static security checks are performed in the order in the expected failure set. Respectively calculating inner layer objective function values after N-1 faults under four control modes until a system does not have a line overload phenomenon after a certain fault, and comparing the advantages and disadvantages of the control modes by taking the maximum value of the objective function under each fault which is calculated;
(6) the particles are evaluated according to the principle that the safety of the system is prior to the economy, and the comparison between the particles and the particles is included. Firstly, comparing whether the particles are overloaded in a normal state or not, secondly, comparing the overload condition of the system after N-1, thirdly, comparing the balance degree of the load flow distribution of the system, lastly, comparing the economic indexes of the particles, updating the individual optimal (pbest) data of each particle according to the comparison result, and replacing the original data in the global optimal (gbest) with the optimal solution in the pbest, wherein the pbest and the gbest comprise traditional control variables, UPFC control parameters and control modes thereof;
(7) updating the position and the velocity vector of each particle through a particle swarm algorithm;
(8) checking whether the maximum iteration times are reached, if not, turning to the step (5), otherwise, turning to the step (9);
(9) and outputting the final UPFC control parameter and the optimization result of the control mode.
The relevant details are as follows:
1. optimizing the model:
2. optimizing variables:
[Vgen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk] (2)；
in the formula, Vgen、PgenT is the location of the OLTC tap for the generator terminal voltage and active power output, C is the capacitance of the parallel compensation capacitor, Vse,θse,VkIs a control variable of the UPFC.
3. And (3) constraint of an equation:
for an uninstalled UPFC node, the following flow balance is satisfied:
where i is 1,2 … N (excluding nodes at both ends of UPFC), and k ∈i denotes a generator connected to the bus i, PGFor active power output of the generator, PLi、QLiAs a load on the bus i, Gij、BijFor conductance and susceptance, theta, on the lines i-jijIs the phase angle difference between two ends of the line i-j, i.e. thetaij＝θi-θj。
For the UPFC installed bus, the bus connecting with the UPFC is recorded as s and r, and the power balance equation of the bus s and r is as follows:
in the formula, Ps(upfc)、Qs(upfc)Injected power, P, for UPFC to bus sr(upfc)、Qr(upfc)The injected power to bus r for UPFC.
Since the UPFC itself cannot generate active power, there are internal constraints on the UPFC itself:
Psh+Pse＝0 (5)；
4. the inequality constrains:
constraint of control variables:
and (3) state variable constraint:
the method comprises the following steps of limiting the voltage of a load node bus and limiting the reactive power output of a generator:
Vmin≤V≤Vmax (7)；
QGmin≤QG≤QGmax (8)；
the invention uses three evaluation indexes of the total number of the out-of-limit lines of the system under the normal operation condition, the total number of the out-of-limit lines of the system under the N-1 state and the static safety margin of the system to form a static safety evaluation function of the system.
Setting the total number of the overload lines as f under the normal condition of the system1(x) The total number of the overload lines in the N-1 state of the system is f2(x) System static safety margin f3(x) In that respect Suppose that the system has n lines, the bus has k lines, and the load factor of the ith line is lambdaiThe voltage of the ith bus is ViThe upper and lower limits of the bus voltage are Vi min，Vi maxThe power generator has m generators, and the output of the ith generator is Pi+jQiThe upper and lower limits are
The distance from the system operating point Q to the static safety limit LM of the line is dlineThe safety margin of the bus voltage is dbus. Defining the static safety margin of the system as follows:
f3(x)＝1/dline+dgen+dbus (9)；
wherein,
in order to comprehensively consider the economy and the safety of the system, the invention adopts the power system operation cost index P (x) to measure the power system operation economy. In addition, the invention adopts a form of adding penalty items to take account of the system safety, the safety of the system is measured by using the above three-level evaluation indexes, when the system is out of limit under normal conditions, the solution is abandoned, when the power flow of the system is out of limit after N-1, corresponding penalty is made to the economic index, and simultaneously, in order to enable the static safety margin of the system to be as high as possible, the static safety margin index of the system is added into the objective function, so that the following objective function is formed:
and (3) comprehensive optimization target:
f(x)＝[N2(x)r+P(x)]f3(x) (13)；
wherein P (x) is the system operating cost, f3(x) Is the inverse of the static safety margin of the system, N2(x) Maximum number of line overload after N-1 of the system, r is penalty coefficient, PlossIs the system loss.
The invention adopts a static safety fault sequencing method as follows:
establishing the following scalar function PI to comprehensively reflect the overload condition of the system:
in the formula: piFor active power on line i, PicFor transmission capacity limits, alpha, on line iiNumber of parallel paths, ω, in line iiNL is the total number of system branches to reflect the weighting factor of the importance of line i.
When the system is not under an overload condition,
the PI indexes are not more than 1 and are small; when there is line overload in the system, the line is overloaded
Above 1, the PI index becomes very large after squaring. The index can reflect the static security of the system.
When the kth line is disconnected, the power flow P on the ith line is calculated by the sensitivity analysis methodi', i ≠ 1,2, … NL and i ≠ k. This is an evaluation function of:
before and after the line is broken, the evaluation index variation is as follows:
ΔPIk＝PI′-PI (18)；
and performing disconnection calculation on all lines in the system, and sequencing the obtained delta PI, wherein the sequence is the sequence of each fault in the expected fault set.
The invention selects an IEEE30 node test system for calculation and analysis, and a system wiring diagram is shown in figure 2. The UPFC is installed between lines 4-6, a UPFC outlet side bus 31 is added, an equivalent circuit diagram of the UPFC is shown in figure 3, a system reference power is 100MVA, and other schematic diagrams are shown in figures 5-10.
The PSO algorithm parameters are as follows: coefficient of inertia w 0.7298, coefficient of acceleration c1＝1.4962，c21.4962, the population size POP is 50, the maximum iteration number Num is 30, the order of system operation cost is calculated by the second chapter, and the penalty coefficient r is calculated2Set to 10000. The iterative convergence diagram is shown in fig. 4.
The values of the control variables after final optimization are shown in table 1, the optimization indexes are shown in table 2, and the calculation results show that the overload circuit does not exist in the system under normal conditions or after N-1, and the system has good static safety margin and running cost level.
Table 1 control parameter results (p.u.)
TABLE 2 optimized indexes
The following describes a preferred control mode of the UPFC. When the set of control parameters is adopted, the faults are sorted, 5 faults which are sorted in the front of all faults are taken, and the system safety index of each control mode of the UPFC after the following circuit is disconnected is calculated, and the result is shown in Table 3. When the UPFC adopts the constant power control mode, the system is not overloaded, and the static safety margin of the system is the highest, so the phase angle regulation control mode of the UPFC is selected.
TABLE 3 inner objective function values of four control modes of UPFC after N-1 fault
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, but any modifications or equivalent variations made according to the technical spirit of the present invention are within the scope of the present invention as claimed.
Claims (7)
1. A comprehensive optimization method for economy and static safety of a power system with a UPFC comprises the following steps:
(1) reading system network data, generator output and load size related data;
(2) setting PSO algorithm basic information related to the population size, the maximum iteration number and the maximum particle velocity value, and initializing the position and the velocity of each particle, wherein the position information of the particle comprises three control variables, namely [ V ] and UPFCgen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk]；
(3) Calculating system power flow under a corresponding operation mode of each particle, calculating system operation cost, namely an outer layer objective function value and a control target under each control mode of the UPFC, and recording whether an overload condition exists or not;
(4) calculating the load flow of each circuit after disconnection by a sensitivity analysis method for the particles without overload, further calculating an evaluation index PI, and sequencing the faults;
(5) performing N-1 static safety verification according to the expected concentrated sequence of faults, respectively calculating inner layer objective function values after the N-1 faults under four control modes until the system does not have a line overload phenomenon after a certain fault, and comparing the advantages and disadvantages of the control modes by taking the maximum value of the objective function under each fault which is calculated;
(6) evaluating the particles according to the principle that the safety of the system is prior to the economy, wherein the evaluation comprises the comparison between the particles, firstly, whether the particles are overloaded in a normal state is compared, secondly, the overload condition of the system after N-1 is compared, secondly, the balance degree of the system power flow distribution is compared, and finally, the economy indexes of the particles are compared, according to the comparison result, the individual optimal pbest data of each particle is updated, the optimal solution in the pbest replaces the original data in the global optimal gbest, and the pbest and the gbest comprise traditional control variables, UPFC control parameters and control modes thereof;
(7) updating the position and the velocity vector of each particle through a particle swarm algorithm;
(8) checking whether the maximum iteration times are reached, if not, turning to the step (5), otherwise, turning to the step (9);
(9) and outputting the final UPFC control parameter and the optimization result of the control mode.
2. The comprehensive optimization method for the economy and the static safety of the UPFC-containing power system as claimed in claim 1, wherein the method comprises the following steps:
optimizing the model in the second step;
where the variables are optimized as:
[Vgen1,…Vgen5,Pgen1,…Pgen5,T1,…T4,C1,C2,Vse,θse,Vk] (2)；
in the formula, Vgen、PgenFor generator terminal voltage and active power, T is the OLTC tap position, C is the capacitance of the parallel compensation capacitor, Vse,θse,VkIs a control variable of the UPFC.
3. The comprehensive optimization method for the economy and the static safety of the UPFC-containing power system as claimed in claim 2, wherein the method comprises the following steps:
carrying out equality constraint on the model in the second step;
for an uninstalled UPFC node, the following flow balance is satisfied:
where i is 1,2 … N, and does not include nodes at both ends of UPFC, k ∈ i denotes a generator connected to the bus i, and P represents a node at both ends of UPFCGFor active power output of the generator, PLi、QLiAs a load on the bus i, Gij、BijFor conductance and susceptance, theta, on the lines i-jijIs the phase angle difference between two ends of the line i-j, i.e. thetaij＝θi-θj；
For the UPFC installed bus, the bus connecting with the UPFC is recorded as s and r, and the power balance equation of the bus s and r is as follows:
in the formula, Ps(upfc)、Qs(upfc)Injected power, P, for UPFC to bus sr(upfc)、Qr(upfc)The injection power of the UPFC to the bus r;
since the UPFC itself cannot generate active power, there are internal constraints on the UPFC itself:
Psh+Pse＝0 (5)。
4. the comprehensive optimization method for the economy and the static safety of the UPFC-containing power system as claimed in claim 2, wherein the method comprises the following steps:
carrying out inequality constraint on the model in the step two;
constraint of control variables:
and (3) state variable constraint:
the method comprises the following steps of limiting the voltage of a load node bus and limiting the reactive power output of a generator:
Vmin≤V≤Vmax (7)；
QGmin≤QG≤QGmax (8)。
5. the comprehensive optimization method for the economy and the static safety of the UPFC-containing power system as claimed in claim 1, wherein the method comprises the following steps:
step six, under the condition of normal operation, the total number of the out-of-limit lines of the system under the N-1 state and the static safety margin of the system form a static safety evaluation function of the system;
setting the total number of the overload lines as f under the normal condition of the system1(x) The total number of the overload lines in the N-1 state of the system is f2(x) System static safety margin f3(x) Suppose that the system has n lines, the bus has k lines, and the load factor of the ith line is lambdaiThe voltage of the ith bus is ViThe upper and lower limits of the bus voltage are Vi min，Vi maxThe power generator has m generators, and the output of the ith generator is Pi+jQiThe upper and lower limits are
The distance from the system operating point Q to the static safety limit LM of the line is dlineThe safety margin of the bus voltage is dbusDefining the system static safety margin as follows:
f3(x)＝1/dline+dgen+dbus (9)；
wherein,
6. the UPFC-containing power system economic and static safety comprehensive optimization method according to claim 5, characterized in that:
the method comprises the following steps of measuring the running economy of the power system by adopting a power system running cost index P (x), measuring the safety of the system by adopting a form of adding a penalty item and the safety of the system by using the three-level evaluation index, giving up the solution when the system is out of limit under normal conditions, giving corresponding penalty to the economy index when the power flow of the system is out of limit after N-1, and adding a system static safety margin index into an objective function so as to enable the system static safety margin to be as high as possible, wherein the following objective function is formed:
and (3) comprehensive optimization target:
f(x)＝[N2(x)r+P(x)]f3(x) (13)；
wherein P (x) is the system operating cost, f3(x) For the static safety margin of the system, N2(x) Maximum number of line overload after N-1 of the system, r is penalty coefficient, PlossIs the system loss.
7. The comprehensive optimization method for the economy and the static safety of the UPFC-containing power system as claimed in claim 1, wherein the method comprises the following steps:
the static safety fault sequencing method adopted in the fifth step is as follows:
establishing the following scalar function PI to comprehensively reflect the overload condition of the system:
in the formula: piFor active power on line i, PicFor transmission capacity limits, alpha, on line iiNumber of parallel paths, ω, in line iiNL is the total number of system branches to reflect the weight coefficient of the importance of the line i;
when the system is not under an overload condition,
the PI indexes are not more than 1 and are small; when there is line overload in the system, the line is overloaded
If the square function is larger than 1, the PI index becomes very large, so that the index can reflect the static safety of the system;
when the k-th line is disconnected, it is calculated by the preceding sensitivity analysis methodObtaining the power flow P on the ith linei', i ═ 1,2, … NL and i ≠ k, which is an evaluation function of:
before and after the line is broken, the evaluation index variation is as follows:
ΔPIk＝PI′-PI (18)；
and performing disconnection calculation on all lines in the system, and sequencing the obtained delta PI, wherein the sequence of sequencing the delta PI is the sequence of each fault in the expected fault set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710834915.6A CN107611965B (en) | 2017-09-15 | 2017-09-15 | UPFC-containing power system economic and static safety comprehensive optimization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710834915.6A CN107611965B (en) | 2017-09-15 | 2017-09-15 | UPFC-containing power system economic and static safety comprehensive optimization method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107611965A CN107611965A (en) | 2018-01-19 |
| CN107611965B true CN107611965B (en) | 2021-11-19 |
Family
ID=61060296
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710834915.6A Expired - Fee Related CN107611965B (en) | 2017-09-15 | 2017-09-15 | UPFC-containing power system economic and static safety comprehensive optimization method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107611965B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108416107B (en) * | 2018-02-05 | 2021-07-06 | 电子科技大学 | Particle motion pushing finite element algorithm applied to PIC |
| CN108390388B (en) * | 2018-02-24 | 2021-06-18 | 国电南瑞科技股份有限公司 | Auxiliary decision calculation method for eliminating overload of near-zone equipment of unified power flow controller |
| CN109149584B (en) * | 2018-09-29 | 2019-12-10 | 东南大学 | Method for improving convergence of IPFC power injection model in load flow calculation |
| CN110277786A (en) * | 2019-07-25 | 2019-09-24 | 东南大学 | Flow controller addressing and constant volume method between a kind of line |
| CN110661264B (en) * | 2019-09-03 | 2023-03-24 | 吉林大学 | Safety constraint optimal power flow calculation method based on particle swarm algorithm with inertial weight |
| CN110661265B (en) * | 2019-09-19 | 2023-03-28 | 吉林大学 | Safety constraint optimal power flow calculation method based on branch circuit breaking distribution factor |
| CN111697588B (en) * | 2020-06-08 | 2022-09-09 | 东南大学 | Prevention control method considering IPFC control mode |
| CN111882126A (en) * | 2020-07-24 | 2020-11-03 | 贵州电网有限责任公司 | N-1-1 static security check optimization method and system |
| CN114389270A (en) * | 2022-01-21 | 2022-04-22 | 东南大学 | Power flow optimization method for power system considering control characteristics of double-circuit IPFC |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105470948A (en) * | 2015-11-24 | 2016-04-06 | 国家电网公司 | Power injection model of power flow controller under direct current power flow model and addressing method thereof |
| CN106655194A (en) * | 2016-11-22 | 2017-05-10 | 国网江苏省电力公司电力科学研究院 | UPFC-considered ATC calculation method of electric power system including wind power |
| CN106684857A (en) * | 2016-09-05 | 2017-05-17 | 国网江苏省电力公司电力科学研究院 | Linear optimal power flow model containing unified power flow controller |
| CN107147124A (en) * | 2017-07-14 | 2017-09-08 | 国网江苏省电力公司经济技术研究院 | A kind of method of UPFC access systems, the node power injection models of UPFC five and tidal current computing method |
-
2017
- 2017-09-15 CN CN201710834915.6A patent/CN107611965B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105470948A (en) * | 2015-11-24 | 2016-04-06 | 国家电网公司 | Power injection model of power flow controller under direct current power flow model and addressing method thereof |
| CN106684857A (en) * | 2016-09-05 | 2017-05-17 | 国网江苏省电力公司电力科学研究院 | Linear optimal power flow model containing unified power flow controller |
| CN106655194A (en) * | 2016-11-22 | 2017-05-10 | 国网江苏省电力公司电力科学研究院 | UPFC-considered ATC calculation method of electric power system including wind power |
| CN107147124A (en) * | 2017-07-14 | 2017-09-08 | 国网江苏省电力公司经济技术研究院 | A kind of method of UPFC access systems, the node power injection models of UPFC five and tidal current computing method |
Non-Patent Citations (3)
| Title |
|---|
| An Improved Power Injection Model for UPFC;Zhigao Huang et;《The 7th Annual IEEE International Conference》;20170804;第1394-1398页 * |
| FACTS 对电力系统静态安全性影响评价指标体系研究;李立 等;《电力系统保护与控制》;20110416;第39卷(第8期);第33-38页 * |
| UPFC 抑制系统区域间低频振荡研究;范子恺 等;《江苏电机工程》;20160131;第35卷(第1期);第20-23页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107611965A (en) | 2018-01-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107611965B (en) | UPFC-containing power system economic and static safety comprehensive optimization method | |
| CN106253335B (en) | Power distribution network planning method with uncertain distributed power supply capacity and access position | |
| CN107425527B (en) | Static safety prevention control method for unified power flow controller | |
| Gao et al. | State‐of‐charge estimation and active cell pack balancing design of lithium battery power system for smart electric vehicle | |
| Jiang et al. | Identification of voltage stability critical injection region in bulk power systems based on the relative gain of voltage coupling | |
| Al-Ammar et al. | Optimal capacitor placement in radial distribution systems using a fuzzy-dragonfly method | |
| Wang et al. | Dynamic equivalent method of PMSG‐based wind farm for power system stability analysis | |
| CN110414810A (en) | Meter and the multiterminal intelligence Sofe Switch Optimal Configuration Method and system for losing load risk | |
| CN110783913A (en) | Group-based optimal power grid topology online optimization method considering expected accident set | |
| CN110661264B (en) | Safety constraint optimal power flow calculation method based on particle swarm algorithm with inertial weight | |
| CN110676877B (en) | Island microgrid tide detection method | |
| Van Dai et al. | Improving Power System Stability with Gramian Matrix‐Based Optimal Setting of a Single Series FACTS Device: Feasibility Study in Vietnamese Power System | |
| CN112653136A (en) | Power electronic multi-feed-in power system key line identification method and system | |
| CN104850757B (en) | A kind of online test method and device of distributed power source harmonic wave | |
| CN114358638B (en) | Method for identifying cascade fault accident chain of wind power-containing alternating current/direct current series-parallel power grid | |
| CN110348598A (en) | A kind of Net Frame of Electric Network planing method | |
| CN115954956A (en) | Method and system for evaluating access capacity of distributed power supply of power distribution network | |
| CN115714421A (en) | Distributed power supply site selection and volume fixing method based on intelligent single particle optimization algorithm | |
| Ye et al. | Comprehensive mitigation strategy of voltage sag based on sensitive load clustering | |
| CN113991652A (en) | Data-driven multi-output calculation method for short-circuit current of IIDG-containing power distribution network | |
| Kumar et al. | Support vector machine based fault section identification and fault classification scheme in six phase transmission line | |
| CN113241793A (en) | Prevention control method for power system with IPFC (intelligent power flow controller) considering wind power scene | |
| CN112491090B (en) | Power electronic transformer port configuration optimization method considering transfer path optimization | |
| CN115276055B (en) | Energy storage configuration method and system based on power grid frequency spatial distribution characteristics | |
| Padmavathi et al. | Comparison of hybrid differential evolution algorithm with genetic algorithm based power system security analysis using FACTS |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20211119 |