CN114421526A - Distributed photovoltaic multi-cluster voltage control method and system and storage medium - Google Patents
Distributed photovoltaic multi-cluster voltage control method and system and storage medium Download PDFInfo
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Abstract
The invention relates to a distributed photovoltaic multi-cluster voltage control method, a system and a storage medium, which comprises the steps of preliminarily determining a safe cluster and a dangerous cluster by utilizing cluster division results and cluster voltage deviation degrees of all clusters, and carrying out local voltage regulation on the dangerous cluster; if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors; selecting a safety cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the voltage deviation degree of each cluster is still in a dangerous cluster, and otherwise, controlling the voltage stability of the power grid level if the voltage deviation degree of each cluster is in a safety margin. The method can be widely applied to the field of voltage control of the power distribution network of the new energy power system.
Description
Technical Field
The invention relates to the field of voltage control of a power distribution network of a new energy power system, in particular to a distributed photovoltaic multi-cluster voltage control method and system based on cluster voltage deviation degrees and a storage medium.
Background
The photovoltaic-based clean energy is rapidly developed in the world due to the advantages of economy, cleanness and environmental protection, and the pressure of fossil energy exhaustion and ecological environment deterioration is greatly relieved. With the continuous improvement of the permeability of the distributed photovoltaic power supply in the power distribution network, the problems of voltage and frequency fluctuation, out-of-limit and the like caused by intermittent output, randomness and large power fluctuation of the distributed photovoltaic power supply are obvious, and huge challenges are brought to the operation of the power distribution network. In order to realize the purpose of realizing the real-time stability of the distribution network voltage under the novel power system, a theoretical basis is laid for the safe and stable operation of the power system under the novel energy structure, and the distributed photovoltaic access post-stable control needs to be researched. The photovoltaic cluster has small inertia, small damping and quick response, and the stable control of the voltage of the cluster becomes a difficult point. The distributed photovoltaic power inverter has the disadvantages of low PV utilization rate, poor economy and large grid voltage fluctuation caused by unreasonable control mode and parameter setting. Therefore, research on a grid-connected reactive-voltage dynamic switching control technology of the distributed photovoltaic power supply clusters and a frequency and voltage active support technology matched among the distributed power supply clusters under a new situation is urgently to be developed, and a decision basis is provided for project construction of high-proportion new energy access.
In recent years, there are many documents for developing research on a distributed photovoltaic power distribution network after-stabilization method, and the following points of interest mainly include: inverter control mode, method for matching with energy storage, changing transformer tap, and corresponding improvement method measures.
At present, voltage regulation means for a distributed photovoltaic system mainly comprise reactive compensation and active reduction. In terms of in-situ reactive compensation, the german institute of electrical engineers proposes four reactive control strategies applicable to distributed photovoltaics: constant reactive power Q control, constant power factor cos phi control, cos phi (P) control based on photovoltaic active output, and Q (U) control based on grid-connected point voltage amplitude. However, as a basic method, the method has various advantages and disadvantages, and the constant reactive power method cannot participate in the voltage regulation of the power grid in time; when the photovoltaic power generation capacity is large and the local load is large, redundant power transmission causes a large amount of loss by the power factor method; the voltage regulation capability of the control mode based on the voltage of the grid-connected point at the position of the grid-connected point is weak. And when the output capacity of the inverter reaches the rated capacity and the voltage is still out of limit, an active reduction method is adopted. The method comprises the following steps of carrying out research on the reactive power regulation capacity of a photovoltaic inverter, establishing a low-voltage distribution network multi-mode voltage control model by combining a reactive voltage sensitivity matrix, and regulating the reactive power of the inverter by taking risk inhibition as a target when the network has voltage out-of-limit operation risk; when the network runs without risk, the optimization of the network loss and the power factor is used as the reactive power regulation basis of the inverter, but the data volume of the whole distribution network is large, the efficiency is low, the real-time performance is poor, and the voltage fluctuation control effect is poor.
Disclosure of Invention
Aiming at the defect of the voltage stability problem after the distributed photovoltaic is connected into a distribution network at present, the invention aims to provide a distributed photovoltaic multi-cluster voltage control method, a system and a storage medium, which can effectively adapt to the adjustment of the operation voltage of a power grid.
In order to achieve the purpose, the invention adopts the following technical scheme: a distributed photovoltaic multi-cluster voltage control method, comprising: preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster; if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors; selecting a safety cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the voltage deviation degree of each cluster is still in a dangerous cluster, and otherwise, controlling the voltage stability of the power grid level if the voltage deviation degree of each cluster is in a safety margin.
Further, the preliminarily determining a safety cluster and a dangerous cluster by using the cluster division result and the cluster voltage deviation degree of each cluster includes: and judging whether the voltage in each cluster exceeds the limit or not by utilizing the cluster division result and the cluster voltage deviation degree of each cluster, wherein if the voltage in each cluster exceeds the limit, the cluster is a dangerous cluster, and otherwise, the cluster is a safe cluster.
Further, the local pressure regulation of the danger cluster includes: and dispatching an inverter with adjustable reactive power capacity in the danger cluster, and switching the inverter into an improved droop control mode to carry out on-site voltage regulation.
Further, the determining of the cluster voltage deviation degree includes: obtaining each photovoltaic cluster microgrid based on a cluster division result; for each node in the cluster, calculating the reactive voltage sensitivity of each node to the leading node; and calculating to obtain the voltage deviation degree of each cluster according to the number of nodes in the cluster and the reactive voltage sensitivity.
Further, the voltage deviation degree is:
in the formula, MθIs the cluster voltage deviation degree; n is the number of nodes in the cluster; u shapeiFor i-node real-time operation of voltage, SiθReactive voltage sensitivity coefficient, U, for node i to dominant node θminFor minimum terminal voltage of each node in the cluster, UmaxAnd the maximum value of the terminal voltage of each node in the cluster.
Further, the total reactive power is:
in the formula,. DELTA.QjIncreasing the total reactive power of the photovoltaic inverter in the safety cluster; sijFor the reactive-voltage sensitivity factor, U, between the safety cluster leader node j and the hazard cluster leader node iminFor minimum terminal voltage of each node in the cluster, UmaxFor maximum terminal voltage of each node in the cluster, UiThe voltage is run in real time for the i-node.
Further, the distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power amount includes:
establishing an active/reactive voltage sensitivity matrix between clusters and between nodes;
obtaining the relation between the node voltage amplitude variation and the power variation according to the node active/reactive voltage sensitivity matrix, and obtaining the difference value between the real-time voltage and the voltage rated value of the node;
and calculating to obtain the photovoltaic reactive variable quantity of each node according to the difference value between the real-time voltage of the node and the rated value, and obtaining the reactive power emitted by each distributed photovoltaic power supply in the cluster according to the photovoltaic reactive variable quantity K of each node and the reactive-voltage sensitivity factor, so that the reactive power is distributed to each distributed photovoltaic power supply in the cluster by the total reactive power quantity.
A distributed photovoltaic multi-cluster voltage control system, comprising: the primary dividing module is used for preliminarily determining a safety cluster and a dangerous cluster by using a cluster dividing result and the cluster voltage deviation degree of each cluster, and carrying out local voltage regulation on the dangerous cluster; the cluster determining module is used for calculating reactive-voltage sensitivity factors among the clusters if the local voltage regulation fails, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors; the power distribution module is used for selecting a safe cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safe cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and the detection module is used for circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the cluster is still in a dangerous cluster, and otherwise, controlling the voltage stability of the power grid level when the voltage of each cluster is within the safety margin.
A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform the method of any of the above claims.
A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the above-described methods.
Due to the adoption of the technical scheme, the invention has the following advantages:
the method is based on voltage and current double closed-loop control, adopts improved droop control and PQ control mode switching on the grid-connected inverter, and establishes a distributed photovoltaic power access distribution network model. And then evaluating the out-of-limit risk of the voltage of each cluster by using the cluster division result and the voltage deviation level index of each cluster, and establishing a reactive voltage sensitivity matrix between each cluster and each node. And finally, the distributed photovoltaic inverters in each cluster are subjected to a voltage self-adaptive control mode, so that the voltage stability of the power grid is realized, and the operation voltage of the power grid can be effectively adaptively adjusted.
Drawings
Fig. 1 is a schematic diagram of a distributed photovoltaic multi-cluster voltage control method according to an embodiment of the present invention;
FIG. 2 is an equivalent circuit diagram of a photovoltaic power supply in one embodiment of the present invention;
FIG. 3 is a grid-connected diagram of a photovoltaic power supply in an embodiment of the present invention;
FIG. 4 is a block diagram of a droop control inverter control in one embodiment of the present invention;
fig. 5 is a distributed photovoltaic access IEEE33 node simulation system in an embodiment of the invention;
FIG. 6 is a schematic diagram of IEEE33 node system voltage levels in one embodiment of the invention;
fig. 7a is a schematic diagram of distributed photovoltaic active output in PQ mode in an embodiment of the invention;
FIG. 7b is a schematic diagram of the distributed photovoltaic reactive output in PQ mode according to an embodiment of the present invention;
fig. 7c is a diagram illustrating a variation of the distributed photovoltaic voltage in the q (u) mode according to an embodiment of the present invention;
fig. 7d is a diagram of distributed photovoltaic reactive power variation in q (u) mode in an embodiment of the present invention;
FIG. 8 is a graph of improved IEEE33 node system reactive voltage sensitivity in one embodiment of the present invention;
fig. 9 is a graph of voltage changes at IEEE33 nodes before and after a regulation mode based on a cluster voltage deviation degree according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The invention provides a distributed photovoltaic multi-cluster voltage control method, a system and a storage medium, wherein the method comprises the following steps: and carrying out cluster division on the distribution network actually containing the distributed photovoltaic according to the improved electrical distance, and setting the grid-connected inverter control mode to be automatically switched according to the cluster voltage deviation degree. And evaluating the out-of-limit level of the voltage of each cluster according to the cluster voltage deviation degree of each cluster, selecting a cluster leading node on the basis of establishing a reactive voltage sensitivity matrix between each cluster and each node, and calculating the sensitivity relation between the leading nodes. And finally, coordinating and matching each safety cluster and each dangerous cluster by adopting a control mode based on the cluster voltage deviation degree so as to realize the voltage stability of the power grid. The method avoids the workload increased by processing a large amount of data of each node of the distribution network and reduces the real-time effectiveness of voltage control, has stronger pertinence and adaptability, and enables the voltage of the power grid to be stabilized in a safety range more quickly.
Aiming at a power distribution network containing high-proportion distributed photovoltaic, the invention takes the electrical distance based on impedance as a grouping index and groups the power distribution network containing distributed photovoltaic, calculates the voltage deviation degree of each cluster, adopts improved droop control based on virtual impedance for clusters with serious out-of-limit, adjusts the voltage of each cluster in the power network by adjusting the reactive power in each cluster which runs safely, and on the basis, monitors the running state of the power network in real time, realizes dynamic cluster division and realizes corresponding control mode switching. The method simplifies the voltage control of the power distribution network, avoids controlling each node, greatly increases the complexity of data processing, and is difficult to operate. Meanwhile, multi-level voltage control is realized through power distribution network grouping of high-proportion photovoltaic access, so that the control method adopted by the invention can track the operation characteristics of the power grid in real time and adopt a corresponding control mode to maintain the voltage stability of the power grid.
In one embodiment of the invention, a distributed photovoltaic multi-cluster voltage control method is provided. In this embodiment, as shown in fig. 1, the method includes the following steps:
1) preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster;
2) if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining the safe cluster and the dangerous cluster according to the reactive-voltage sensitivity factors;
3) selecting a safety cluster with the maximum sensitivity factor between a main guide node and a dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity;
4) and circularly detecting the voltage deviation degree of each cluster, if the voltage deviation degree of each cluster is still in a dangerous cluster, re-determining the safe cluster, and otherwise, enabling the voltage of each cluster to be within a safety margin, so as to realize the control of the voltage stability of the power grid.
In this embodiment, a distributed photovoltaic power access distribution network model needs to be established. Firstly, a photovoltaic power side model is established, as shown in fig. 2, the output current I of the photovoltaic power is:
wherein ISCFor short-circuit current of photovoltaic cells, IdIs a diode saturation current, IShIs the leakage current of the photovoltaic cell, I0For reverse saturation current, RSIs a series equivalent resistance, RshThe equivalent resistance is parallel connection, and U is output voltage of the photovoltaic power supply.
Considering engineering practicability, establishing a photovoltaic power supply practical mathematical model, wherein the output current I of the photovoltaic power supply is as follows:
wherein U is the output voltage of the photovoltaic power supply, C1Is a current proportionality coefficient, C2Is a current index coefficient; u shapeocIs open circuit voltage, UmAt maximum power voltage, ImThe maximum power current. The active power P output (absorbed by the load) of the PV power supply is:
wherein R is1Is a load resistance, X1Is a load impedance, R0For internal resistance of power supply, X0Is the power supply internal reactance.
When X is present0+X1When 0, the power may have a maximum value, and is substituted for equation (1-5) and derived:
so the condition for the load to obtain the maximum power is R1＝R0，X1＝-X0. At this time, the load ZLThe maximum active power consumed is
Need attention toIs Z0The same value of power is consumed, the maximum power transmission efficiency is 50 percent, and Z is0Is the power supply impedance. And maximum power point tracking control can be realized by adopting methods such as an interference observation method and the like.
Then, a photovoltaic grid-connected model is established, as shown in fig. 3, a photovoltaic grid-connected inverter is connected into a power grid and is connected with a filter inductor and a filter capacitor L through a filter inductormThe voltage equation is:
where m is a controllable sinusoidal modulation signal, IpvFor an inverter output current, VLIs a load voltage vector, k is a voltage modulation factor, VpvIs the output voltage of the inverter, omega is the angular frequency of the three-phase electrical quantity, t is the operation time,
i is the initial phase angle and the phase coefficient. Neglecting filter resistance R connected with inverterm(the value is small), the filter capacitor current equation can be written as:
wherein, CmTo the size of the filter capacitance, ILTo flow to the load current magnitude, IPccIs the magnitude of the current flowing to the grid connection point.
The outer ring is controlled to be a voltage ring, the function of stabilizing the load voltage to a given voltage is realized by combining PI control, and the inner ring is controlled to be a current ring, so that the dynamic response capability of the system is improved.
When the three phases of the photovoltaic power grid-connected model are symmetrical, the filter outputs a load voltage vector (load side voltage) VLAnd an inverter outputVoltage VpvThe transfer function of (a) is shown in the following equation (1-10).
In the formula,
after the distributed photovoltaic is connected into the power distribution network, when the photovoltaic is controlled by a unit power factor, the active output is far larger than the local load, and the reactive loss is ignored, the voltage of the power distribution network is set to be VPCCThen, there are:
in the formula, PpvThe inverter output active power is shown, and X represents the system equivalent reactance.
If the voltage of the grid-connected point is kept unchanged before and after the grid-connected point is connected into the photovoltaic, the voltage difference increment of the longitudinal axis is ignored, and the required emitted reactive power Q isPVThe size is as follows:
in the formula, QLRepresenting reactive power of the load, PLRepresenting the load active power.
In the step 1), the safety cluster and the dangerous cluster are preliminarily determined by using the cluster division result and the cluster voltage deviation degree of each cluster, and the method specifically comprises the following steps: and judging whether the voltage in each cluster exceeds the limit or not by utilizing the cluster division result and the cluster voltage deviation degree of each cluster, and if so, determining that the cluster is a dangerous cluster, otherwise, determining that the cluster is a safe cluster.
Wherein, carry out local pressure regulating to dangerous cluster: and dispatching the inverters with adjustable reactive power capacity in the danger cluster, and switching the inverters into an improved droop control mode to carry out local voltage regulation.
In this embodiment, in inverter control, the basic control principle of Q (u) is as shown in fig. 4, and when a voltage source inverter topology is adopted for photovoltaic grid connection, calculating the output active power P and the output reactive power Q of an inverter based on an abc three-phase stationary coordinate system are respectively as follows:
wherein, thetaiIs the impedance power factor angle between the inverter and the grid-connected point, alpha is the voltage angle difference between the output end of the inverter and the grid-connected point, ZmIs line impedance, UpvTo the inverter terminal voltage, UpccIs the dot-on-screen voltage.
Taking two distributed photovoltaic grid-connected inverters connected in parallel as an example, when the line impedance Z ismWhen perceptual appearance is dominant:
the frequency is integrated and then is the phase angle, namely:
wherein f isσTo a nominal frequency, ασAt nominal power angle, XmFor load reactance, t0 is the integration calculation end time.
The corresponding droop control expression is:
wherein, PmOutputting active power for photovoltaic actual measurement, wherein f is photovoltaic actual measurement frequency fσRated frequency for photovoltaic, KPIs the active sag factor, KqIs a reactive sag coefficient, UσIs the photovoltaic rated output voltage.
Carrying out park transformation on three-phase voltage and current of a distributed photovoltaic grid-connected inverter end measured in real time to respectively obtain voltage and current dq axis components, realizing power decoupling calculation and a park transformation matrix Tabc/dqComprises the following steps:
where ω is the angular frequency of the three-phase electrical quantity. The three-phase voltage and current are subjected to park transformation to obtain dq axis components of u respectivelymd、umq、imd、imqAnd calculating the output power of the inverter at the moment:
p＝umdimd+umqimq (1-21)
q＝umqimd-umdimq (1-22)
and power grid voltage directional vector control is adopted, the current at the output side of the photovoltaic grid-connected inverter, the d axis of the synchronous rotating coordinate system and the power grid voltage vector synchronously rotate, and the d axis of the synchronous rotating coordinate system and the power grid voltage vector are in the same direction, so that power decoupling is realized, and the inverter PQ control and droop control strategy is realized on the basis.
After the inverter outputs the instantaneous power measurement, since the high frequency component changes rapidly and the amplitude is generally small, the controller may operate unnecessarily frequently, and the service life of the controller is reduced, the high frequency component needs to be removed by a low pass filter to enhance the system stability:
wherein ω isσThe cut-off frequency of the low-pass filter.
For a distributed photovoltaic cluster adopting droop control, the internal power of the photovoltaic cluster is distributed according to capacity to prevent the inverter from being overloaded and damaged to cause further voltage fluctuation and even exceed the limit, and when the system is in a stable running state, the working frequency of each unit in the cluster is the same, namely omega1＝ω2Therefore, according to the equations (1-15) and (1-18), it is only necessary that all inverters in the cluster have the same reference frequency and the same droop coefficient (K) under the rated active power1P、K2P) Constant power
The ratio satisfies the formulas (1-25) and (1-26):
ω1 σ＝ω2 σ (1-25)
the active power output by the inverter can be evenly divided in the cluster according to the rated power:
K1PP1m＝K2PP2m (1-27)
from the expressions (1-16) and (1-19), it can be seen that the capacity E is a prerequisite for realizing the reactive power allocation to the capacity, that is, (1-30) is satisfied, on the premise that (1-28) and (1-29) are satisfied1＝E2。
U1 σ＝U2 σ (1-28)
At the moment, the output reactive power of the inverter can be evenly divided in the cluster according to the rated power:
K1qQ1m＝K2qQ2m (1-30)
the slope in the reactive voltage droop control curve is generally small, small disturbance deviation between voltages can cause large reactive difference, and the inverter overcurrent can occur. When (1-28) and (1-29) are established, the voltage difference between the distributed photovoltaics in the cluster is:
ΔU＝U2-U1＝K2qQ2m-K1qQ1m (1-31)
substituting formula (1-19) for formula (1-16)
Substituting formula (1-32) for formula (1-31)
The final derivation formula (1-33) can obtain that on the premise that (1-28) and (1-29) are established, U can be ensured only when the reactive voltage droop coefficient control of the distributed photovoltaic inverters in the cluster is in inverse proportion to impedance2＝U1And further, the reactive power is uniformly distributed according to the capacity in the cluster.
The method for determining the range of the improved droop control coefficient adopted in the embodiment comprises the following steps: the power per capacity allocation is achieved in consideration of the distributed photovoltaic access virtual impedance. Determining the proportion of droop coefficients in the distributed photovoltaic clusters, and deducing a reactive droop control coefficient in order to select a proper size:
setting N nodes, b branches in the cluster, Evir、Eσ、P、Q、PL、QLU is respectively virtual grid-connected voltage, rated reference voltage, active power output by each node distributed photovoltaic/energy storage, reactive power output by each node distributed photovoltaic, active load, reactive load, voltage matrix of each node, E0Is a rated voltage matrix, Rm、Xm、 KqRespectively a virtual resistance, a virtual reactance, a reactive droop coefficient n multiplied by n diagonal array, Ub、Pb、QbThe line voltage drop, the transmission active power and the transmission reactive matrix are respectively. Rb、XbThe matrix is a line resistance and reactance matrix, and M is a node correlation matrix.
And Q' is the reactive power output by each distributed PV when the reactive power is distributed according to the capacity in the cluster. The virtual output voltage of each distributed photovoltaic power supply is as follows:
Evir＝Eσ-KqQ (1-34)
the terminal voltage of each node in the cluster is as follows:
the voltage drop across the branch is:
from kirchhoff's current law, there are:
Ub＝MTU (1-37)
the power flow balance equation of each node comprises:
Pb＝MT(P-PL) (1-38)
Qb＝MT(Q-QL) (1-39)
from the formula (1-34) -the formula (1-39):
[M(E0Kq+Xm)+XbMT]Q＝E0MTEσ-(MTRm+RbMT)P+RbMTPL+XbMTQL (1-40)
according to the foregoing analysis, the capacity allocation that can be achieved in real time is as follows:
P＝KE1×nPL (1-41)
in addition, because the active and reactive share ratio of the distributed power supply is the same under general conditions, the following conditions are provided:
Q’＝KE1×nQL (1-43)
the reactive power matrix equation during the actual operation of the power grid is as follows:
Q＝Q’+ΔQ (1-44)
QLQ＝Q’+ΔQL (1-45)
and because:
then the formula (1-40) can be expressed as:
[M(E0Kq+Xm)+XbMT]Q
＝(MTXm+XbMT)Q’-[(MTRm+RbMT)KE1×n-RbMT]PL+XbMTQL (1-47)
and (4) substituting the system parameters of the microgrid cluster into the formula (1-43) -formula (1-47) to determine the selection range of the droop coefficient.
In the step 1), the determining of the cluster voltage deviation degree includes the following steps:
1.1) obtaining each photovoltaic cluster microgrid based on a cluster division result;
1.2) for each node in the cluster, calculating the reactive voltage sensitivity of each node to the leading node;
and 1.3) calculating according to the number of nodes in the cluster and the reactive voltage sensitivity to obtain the voltage deviation degree of each cluster.
Wherein, the voltage deviation degree is:
in the formula, MθIs the cluster voltage deviation degree; n is the number of nodes in the cluster; u shapeiFor i-node real-time operation of voltage, SiθReactive voltage sensitivity coefficient, U, for node i to dominant node θminFor minimum terminal voltage of each node in the cluster, UmaxAnd the maximum value of the terminal voltage of each node in the cluster.
In this embodiment, the reactive voltage sensitivity relationship between clusters and between nodes is calculated, and voltages of all nodes in a cluster are input into a cluster control system to obtain a voltage deviation degree of each cluster, so as to obtain an operation control mode of each cluster and a system parameter in a corresponding mode.
In the step 1.1), the cluster division method includes the following steps:
determining a modularity index: the strength of the cluster structure is usually explained by external features of the clusters, such as the degree of internal association, the degree of association between clusters, the number of clusters, the scale of the cluster size, the rationality of the cluster logic. The modularization index can quantitatively describe the external characteristics of the community. The modularity index quantifies the structural strength of the community and determines the optimal number of partitions between each partition, defined as follows:
in the formula AijRepresents the weight of the edge of the node i and the node j, sigmajAijAnd if the i node and the j node are classified into the same cluster, the value of delta (i, j) is 1, and otherwise, the value is 0, wherein the level of modularity close to 1 reflects the connection compactness of the nodes in the cluster.
Determining the electrical distance: the electrical relationship of the nodes has larger significance compared with the spatial distance, so that the electrical distance is selected as a calculation modularity index of the weighted adjacency matrix, and the structural performance of the divided clusters and the strength of the electrical relationship are measured. In engineering practice, in order to simplify the method of obtaining the electrical distance, a node impedance matrix is often used to represent the electrical distance matrix. In the cluster division method mentioned in the present invention, the electrical distance between the grounding points is still represented by the impedance matrix, but the two-port network input impedance Z is adoptedij' denotes the electrical distance to the non-grounded point:
Zij′＝Zii+Zjj-2Zij (2-2)
in the step 1.2), the leading node is: the cluster leader node is selected mainly according to monitoring and control of the node voltage. That is, the selected cluster dominant node is both observable and controllable. According to the characteristics of a cluster leading node, calculating the comprehensive sensitivity S of all nodes in the distributed power supply cluster, wherein the leading node with the maximum S value is:
maxS＝max(V+dC) (2-4)
wherein V represents the observability of the node, C represents the controllability of the node, and d is a weight coefficient.
Wherein N is all nodes in the clusterThe set of (a) and (b),
the node voltage sensitivity of the node j to the node i, n is a controllable node set connected with distributed photovoltaic/energy storage equipment in the cluster,
reactive voltage sensitivity of the voltage amplitude at node i relative to the reactive power injected at node j.
In the step 3), the total reactive power is:
in the formula,. DELTA.QjIncreasing the total reactive power of the photovoltaic inverter in the safety cluster; sijFor the reactive-voltage sensitivity factor, U, between the safety cluster leader node j and the hazard cluster leader node iminFor minimum terminal voltage of each node in the cluster, UmaxFor maximum terminal voltage of each node in the cluster, UiThe voltage is run in real time for the i-node.
In the step 3), distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power amount includes the following steps:
3.1) establishing an active/reactive voltage sensitivity matrix between clusters and nodes;
in this embodiment, as known from the Jacobi matrix of the load flow of the power system, the flow calculation in the power distribution network satisfies the following equation:
the matrix transformation of the above equation is:
the active/reactive voltage sensitivity matrix is:
3.2) obtaining the relation between the node voltage amplitude variation and the power variation according to the node active/reactive voltage sensitivity matrix, and obtaining the difference value delta U between the real-time voltage and the voltage rated value of the node;
in this embodiment, according to the active/reactive voltage sensitivity matrix of the node, when n nodes in the cluster contain distributed photovoltaic/energy storage, the relationship matrix between the node voltage amplitude variation and the power variation is as follows:
ΔU＝SUPΔP+SUQΔQ (3-5)
the voltage Vi of each node in the cluster is not only influenced by the power change of the node, but also influenced by the magnitude of active power and reactive power injected by other nodes:
and 3.3) calculating according to the difference between the real-time voltage of the node and the rated value to obtain the photovoltaic reactive variable quantity of each node, and obtaining the reactive power emitted by each distributed photovoltaic power supply in the cluster according to the photovoltaic reactive variable quantity K of each node and the reactive-voltage sensitivity factor to realize the distribution of the total reactive power to each distributed photovoltaic power supply in the cluster.
In this embodiment, as can be seen from equation (3-1), the voltage of the current cluster or other clusters is changed by changing the distributed photovoltaic output in a reactive manner, and the voltage amplitude change at the same point is affected by the change of the power of the distributed photovoltaic output accessed at different positions. In order to calculate the photovoltaic reactive variation K of each node, the power of each node needs to be reasonably distributed according to the reactive voltage sensitivity relationship of each node in the cluster. When the difference between the real-time voltage of the node a and the rated value is known to be Δ U, the following conditions exist:
wherein,
is the reactive-voltage sensitivity coefficient.
Then calculating the reactive power generated by each distributed photovoltaic power supply in the cluster as follows:
in the formula ofiThe value of the Boolean quantity is 1 when the node i in the cluster is connected with the distributed photovoltaic power supply and adjustable power exists, and is 0 otherwise.
Example (b):
an IEEE33 node model containing a high-proportion distributed photovoltaic power distribution network is built by adopting MATLAB/Simulink, the models of the units are the same, and the model is shown in figure 5. The distributed photovoltaic is connected into a power distribution network through a transformer (311V/12.66kV), wherein a node 1 is a grid-connected point of the power distribution network connected to a large power grid.
The clusters and nodes are defined as follows: in this embodiment, the considered nodes are bus bars of the power distribution network, the nodes in the example are 33 bus bars of IEEE33 nodes, the cluster in the example refers to each cluster microgrid after the cluster division of the power distribution network with distributed photovoltaic access, and each cluster in the example is each microgrid system composed of a plurality of nodes in a dashed frame in fig. 5.
Clustering results based on IEEE33 node power distribution network system partitioning using the electrical distance clustering algorithm are shown in table 1.
TABLE 1 clustering results
When the photovoltaic system is not connected, if the grid-connected point voltage is set to the rated voltage of 12.66KV, the IEEE33 node voltage diagram shown in fig. 6 is obtained.
And building a grid-connected model of the distributed photovoltaic power supply through an inverter, wherein the grid-connected model comprises a photovoltaic power supply adopting PQ power decoupling control and a photovoltaic power supply model adopting improved droop control suitable for grid-connected point voltage. The irradiance is unchanged in a short time, namely P is unchanged, and reactive power is changed to enable distributed photovoltaic to participate in voltage regulation between clusters/in the clusters. The latter is set at the time 0.02s when the dot-on-dot voltage rises.
As shown in fig. 7a to 7d, it can be seen that in the power decoupling control mode, when the magnitude of reactive output is independently changed to participate in voltage regulation while the magnitude of active output is unchanged, the magnitude of active output is not affected, decoupling control is realized, and in the q (u) control mode, when the voltage of a monitoring point is increased, the magnitude of reactive output is automatically reduced to participate in voltage regulation, so that voltage fluctuation can be reduced, and local voltage can be effectively regulated to approach rated voltage.
And calculating the voltage change of other nodes caused by the unit reactive power change of a certain node, namely the reactive voltage sensitivity, and generating a sensitivity factor graph shown in fig. 8, wherein the x axis is the unit reactive power change node, the y axis is the voltage change node, and the z axis is the per unit value of the voltage increase of the corresponding node after the unit reactive power change.
Through calculation, the control modes of the cluster containing the distributed photovoltaic according to the cluster voltage deviation degree are respectively as follows: the voltage deviation degree of a cluster 5 containing the photovoltaic clusters 20 and 22 connected to the photovoltaic cluster is within a stability margin, the voltage deviation degree of the cluster is 0.005348, PQ control can be adopted to participate in voltage regulation of a power grid, the photovoltaic nodes 20 and 22 in the cluster 5 still have reactive margin, the reactive voltage sensitivity relationship of the clusters is known, when the reactive power of the nodes 20 and 22 is increased, the voltages of the dangerous clusters 3, 4 and 7 are increased, and the coordination and coordination rationality between the clusters is verified. Other safety clusters can participate in the regulation and control of the power grid level voltage by adopting the same method.
The voltage deviation degree of the photovoltaic cluster 7 with the 31 nodes is large, the voltage deviation degree of the cluster is 0.0533, improved droop control based on virtual impedance is adopted, and the photovoltaic in the cluster participates in voltage regulation. The voltage deviation degree of a photovoltaic cluster 3 containing 14 and 16 nodes is large, the voltage deviation degree of the cluster is 0.0606, improved droop control based on virtual impedance is adopted, and photovoltaic participates in voltage regulation. The voltage deviation degree of the photovoltaic cluster 4 with 18 nodes is large, the voltage deviation degree of the cluster is 0.0647, improved droop control based on virtual impedance is adopted, and photovoltaic participates in voltage regulation. The system voltage levels before and after optimization of each method are shown in fig. 9 in comparison to the cluster-based PQ control method.
Fig. 9 shows that in the conventional PQ control method, the cluster 3 still exceeds the limit and the voltage deviation degree is 0.0506, but the cluster voltage control method proposed herein makes the distribution network voltage recovery level obvious, and the voltage deviation degree recovered by each cluster to the safety level is calculated and reduced to below 0.05, which shows that the cluster voltage control method has better voltage regulation capability, and verifies the rationality of the cluster voltage deviation degree-based voltage regulation control method proposed herein.
When the number of nodes of a power distribution network structure is complex, single power grid level control needs huge processing data, real-time control requirements are difficult to meet, the data processing efficiency is low, the required control effect is difficult to achieve, single station level control can only be regulated and controlled according to local information, and the voltage coordination of all nodes is difficult to maximize, so that the voltage control effect of a cluster level serving as a comprehensive method is remarkably improved, and the actual distribution network containing distributed photovoltaic is divided into clusters according to the improved electrical distance. The grid-connected inverter control mode is set to be automatically switched according to the voltage out-of-limit level. And then evaluating the voltage out-of-limit level of each cluster according to the cluster voltage deviation degree index of each cluster, selecting the leading node of each cluster based on the reactive voltage sensitivity matrix among the nodes, and calculating the voltage sensitivity relation among the clusters. And finally, a voltage control mode based on the cluster voltage deviation degree is adopted for the distributed photovoltaic inverters in each cluster, so that the voltage stability of the power grid is further realized. The voltage control mode of the cluster voltage deviation degree is as follows: when the voltage deviation degree of a certain cluster exceeds a set threshold value, the certain cluster is a dangerous cluster, and the cluster preferentially adopts improved Q (U) mode local voltage control; and selecting other safety clusters with the voltage deviation degree within the threshold safety range, selecting the safety cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, increasing delta Q by an inverter in the safety cluster, returning to judge whether the dangerous cluster enters a safety domain, and selecting the safety cluster to cooperate with pressure regulation if the dangerous cluster does not enter the safety domain. And the reactive power distribution rule in the safety cluster is that the inverters with adjustable reactive power capacity are distributed in proportion according to the size of the sensitivity factor. The method simplifies the voltage control of the power grid, avoids the workload increase caused by processing a large amount of data of each node of the distribution network and reduces the real-time effectiveness of the voltage control. Meanwhile, different control modes are adopted for each cluster, so that the method has stronger pertinence and adaptability, and the coordination control between the clusters is considered, so that the voltage of the power grid is stabilized in a safety range more quickly.
In summary, the method is based on voltage and current double closed-loop control, the grid-connected inverter is switched by adopting an improved droop control mode and a PQ control mode, and a distributed photovoltaic power supply access distribution network model is established. And then evaluating the out-of-limit risk of the voltage of each cluster by using the cluster division result and the voltage deviation level index of each cluster, and establishing a reactive voltage sensitivity matrix between each cluster and each node. And finally, adopting a voltage self-adaptive control mode for the distributed photovoltaic inverters in each cluster to further realize the voltage stabilization of the power grid. The results of example simulation show that the adopted cluster voltage supporting method can effectively adapt to the adjustment of the power grid operating voltage, so that the effectiveness of the method is verified.
In one embodiment of the present invention, there is provided a distributed photovoltaic multi-cluster voltage control system, comprising:
the primary dividing module is used for preliminarily determining a safety cluster and a dangerous cluster by using the cluster dividing result and the cluster voltage deviation degree of each cluster, and carrying out local voltage regulation on the dangerous cluster;
the cluster determining module is used for calculating reactive-voltage sensitivity factors among clusters if local voltage regulation fails, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors;
the power distribution module is used for selecting a safe cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safe cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity;
and the detection module is used for circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the voltage deviation degree of each cluster is still in the dangerous cluster, and otherwise, controlling the voltage stability of the power grid level when the voltage of each cluster is within the safety margin.
The system provided in this embodiment is used for executing the above method embodiments, and for details of the process and the details, reference is made to the above embodiments, which are not described herein again.
In an embodiment of the present invention, a computing device structure is provided, where the computing device may be a terminal, and the computing device structure may include: a processor (processor), a communication Interface (communication Interface), a memory (memory), a display screen and an input device. The processor, the communication interface and the memory are communicated with each other through a communication bus. The processor is used to provide computing and control capabilities. The memory includes a nonvolatile storage medium storing an operating system and a computer program that is executed by a processor to implement a control method; the internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The communication interface is used for carrying out wired or wireless communication with an external terminal, and the wireless communication can be realized through WIFI, a manager network, NFC (near field communication) or other technologies. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on a shell of the computing equipment, an external keyboard, a touch pad or a mouse and the like. The processor may call logic instructions in memory to perform the following method: preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster; if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining the safe cluster and the dangerous cluster according to the reactive-voltage sensitivity factors; selecting a safety cluster with the maximum sensitivity factor between a main guide node and a dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and circularly detecting the voltage deviation degree of each cluster, if the voltage deviation degree of each cluster is still in a dangerous cluster, re-determining the safe cluster, and otherwise, enabling the voltage of each cluster to be within a safety margin, so as to realize the control of the voltage stability of the power grid.
In addition, the logic instructions in the memory may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
Those skilled in the art will appreciate that the configurations of the above-described computing devices are merely some of the configurations associated with the present application and do not constitute limitations on the computing devices to which the present application may be applied, as a particular computing device may include more or fewer components, or some of the components may be combined, or have a different arrangement of components.
In one embodiment of the invention, a computer program product is provided, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions that, when executed by a computer, enable the computer to perform the methods provided by the above-described method embodiments, for example, comprising: preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster; if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining the safe cluster and the dangerous cluster according to the reactive-voltage sensitivity factors; selecting a safety cluster with the maximum sensitivity factor between a main guide node and a dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and circularly detecting the voltage deviation degree of each cluster, if the voltage deviation degree of each cluster is still in a dangerous cluster, re-determining the safe cluster, and otherwise, enabling the voltage of each cluster to be within a safety margin, so as to realize the control of the voltage stability of the power grid.
In one embodiment of the invention, a non-transitory computer-readable storage medium is provided, which stores server instructions that cause a computer to perform the methods provided by the above embodiments, for example, including: preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster; if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining the safe cluster and the dangerous cluster according to the reactive-voltage sensitivity factors; selecting a safety cluster with the maximum sensitivity factor between a main guide node and a dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity; and circularly detecting the voltage deviation degree of each cluster, if the voltage deviation degree of each cluster is still in a dangerous cluster, re-determining the safe cluster, and otherwise, enabling the voltage of each cluster to be within a safety margin, so as to realize the control of the voltage stability of the power grid.
The implementation principle and technical effect of the computer-readable storage medium provided by the above embodiments are similar to those of the above method embodiments, and are not described herein again.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A distributed photovoltaic multi-cluster voltage control method is characterized by comprising the following steps:
preliminarily determining a safety cluster and a dangerous cluster by using cluster division results and cluster voltage deviation degrees of the clusters, and carrying out local voltage regulation on the dangerous cluster;
if the local voltage regulation fails, calculating reactive-voltage sensitivity factors among the clusters, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors;
selecting a safety cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safety cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity;
and circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the voltage deviation degree of each cluster is still in a dangerous cluster, and otherwise, controlling the voltage stability of the power grid level if the voltage deviation degree of each cluster is in a safety margin.
2. The distributed photovoltaic multi-cluster voltage control method of claim 1, wherein the preliminary determination of the safety cluster and the danger cluster by using the cluster division result and the cluster voltage deviation degree of each cluster comprises: and judging whether the voltage in each cluster exceeds the limit or not by utilizing the cluster division result and the cluster voltage deviation degree of each cluster, wherein if the voltage in each cluster exceeds the limit, the cluster is a dangerous cluster, and otherwise, the cluster is a safe cluster.
3. The distributed photovoltaic multi-cluster voltage control method of claim 1, wherein the locally regulating the voltage of the hazardous cluster comprises:
and dispatching an inverter with adjustable reactive power capacity in the danger cluster, and switching the inverter into an improved droop control mode to carry out on-site voltage regulation.
4. The distributed photovoltaic multi-cluster voltage control method of claim 1, wherein the determining of the cluster voltage deviation degree comprises:
obtaining each photovoltaic cluster microgrid based on a cluster division result;
for each node in the cluster, calculating the reactive voltage sensitivity of each node to the leading node;
and calculating to obtain the voltage deviation degree of each cluster according to the number of nodes in the cluster and the reactive voltage sensitivity.
5. The distributed photovoltaic multi-cluster voltage control method of claim 1, wherein the degree of voltage deviation is:
in the formula, MθIs the cluster voltage deviation degree; n is the number of nodes in the cluster; u shapeiFor i-node real-time operation of voltage, SiθReactive voltage sensitivity coefficient, U, for node i to dominant node θminFor minimum terminal voltage of each node in the cluster, UmaxAnd the maximum value of the terminal voltage of each node in the cluster.
6. The distributed photovoltaic multi-cluster voltage control method of claim 1, wherein the total amount of reactive power is:
in the formula,. DELTA.QjIncreasing the total reactive power of the photovoltaic inverter in the safety cluster; sijFor the reactive-voltage sensitivity factor, U, between the safety cluster leader node j and the hazard cluster leader node iminFor minimum terminal voltage of each node in the cluster, UmaxFor maximum terminal voltage of each node in the cluster, UiThe voltage is run in real time for the i-node.
7. The method of claim 1, wherein distributing reactive power to distributed photovoltaic power sources within a cluster based on the total amount of reactive power comprises:
establishing an active/reactive voltage sensitivity matrix between clusters and between nodes;
obtaining the relation between the node voltage amplitude variation and the power variation according to the node active/reactive voltage sensitivity matrix, and obtaining the difference value between the real-time voltage and the voltage rated value of the node;
and calculating to obtain the photovoltaic reactive variable quantity of each node according to the difference value between the real-time voltage of the node and the rated value, and obtaining the reactive power emitted by each distributed photovoltaic power supply in the cluster according to the photovoltaic reactive variable quantity K of each node and the reactive-voltage sensitivity factor, so that the reactive power is distributed to each distributed photovoltaic power supply in the cluster by the total reactive power quantity.
8. A distributed photovoltaic multi-cluster voltage control system, comprising:
the primary dividing module is used for preliminarily determining a safety cluster and a dangerous cluster by using a cluster dividing result and the cluster voltage deviation degree of each cluster, and carrying out local voltage regulation on the dangerous cluster;
the cluster determining module is used for calculating reactive-voltage sensitivity factors among the clusters if the local voltage regulation fails, and re-determining a safe cluster and a dangerous cluster according to the reactive-voltage sensitivity factors;
the power distribution module is used for selecting a safe cluster with the maximum sensitivity factor between the main guide node and the dangerous cluster main guide node in each cluster, enabling an inverter in the safe cluster to increase the total reactive power quantity delta Q, and distributing reactive power to each distributed photovoltaic power supply in the cluster based on the total reactive power quantity;
and the detection module is used for circularly detecting the voltage deviation degree of each cluster, re-determining the safe cluster if the cluster is still in a dangerous cluster, and otherwise, controlling the voltage stability of the power grid level when the voltage of each cluster is within the safety margin.
9. A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-7.
10. A computing device, comprising: one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-7.
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| CN115441463A (en) * | 2022-09-30 | 2022-12-06 | 西南交通大学 | Distributed photovoltaic power generation system voltage control method considering no communication connection |
| WO2023274428A3 (en) * | 2022-03-14 | 2023-02-16 | 国网新疆电力有限公司电力科学研究院 | Power distribution method for photovoltaic power storage station group to participate in power grid stability control |
-
2022
- 2022-01-20 CN CN202210065654.7A patent/CN114421526A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023274428A3 (en) * | 2022-03-14 | 2023-02-16 | 国网新疆电力有限公司电力科学研究院 | Power distribution method for photovoltaic power storage station group to participate in power grid stability control |
| CN115441463A (en) * | 2022-09-30 | 2022-12-06 | 西南交通大学 | Distributed photovoltaic power generation system voltage control method considering no communication connection |
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