CN108183501B - Photovoltaic system common connection point voltage control method considering three-phase imbalance - Google Patents
Photovoltaic system common connection point voltage control method considering three-phase imbalance Download PDFInfo
- Publication number
- CN108183501B CN108183501B CN201711350422.1A CN201711350422A CN108183501B CN 108183501 B CN108183501 B CN 108183501B CN 201711350422 A CN201711350422 A CN 201711350422A CN 108183501 B CN108183501 B CN 108183501B
- Authority
- CN
- China
- Prior art keywords
- adjustment
- voltage
- reactive
- active
- energy storage
- 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.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000004146 energy storage Methods 0.000 claims abstract description 71
- 230000009467 reduction Effects 0.000 claims abstract description 11
- 230000008569 process Effects 0.000 claims description 16
- 238000012545 processing Methods 0.000 abstract description 13
- 238000010521 absorption reaction Methods 0.000 description 10
- 230000035945 sensitivity Effects 0.000 description 5
- 238000010248 power generation Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Images
Classifications
-
- H02J3/383—
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/48—Controlling the sharing of the in-phase component
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/50—Controlling the sharing of the out-of-phase component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a photovoltaic system common connection point voltage control method considering three-phase unbalance, which comprises the following steps of: calculating the voltage deviation of the public connection point of each node, and judging whether the voltage deviation of the public connection point meets the voltage deviation standard or not; if the voltage deviation is larger than the maximum voltage deviation standard, voltage reduction processing is carried out through the photovoltaic inverter and/or the energy storage device, and if the voltage deviation is smaller than the minimum voltage deviation standard, voltage boosting processing is carried out through the photovoltaic inverter and/or the energy storage device. According to the invention, the continuous control of the voltage of the public connection point is realized by coordinately controlling the active power and the reactive power of the photovoltaic inverter and the energy storage device, the consumption of new energy is ensured, the reactive power adjusting capability of the photovoltaic inverter is equivalently increased, the problem of three-phase imbalance is improved, and the quality of electric energy is improved.
Description
Technical Field
The invention relates to the field of photovoltaic power generation, in particular to a photovoltaic system common connection point voltage control method considering three-phase imbalance.
Background
In recent years, with the increasing maturity of photovoltaic power generation technology, the permeability of distributed photovoltaic in power distribution networks, especially low-voltage power distribution networks, is increasing. In a power distribution network with high photovoltaic permeability, particularly a weak radial low-voltage power distribution network, the fluctuation and randomness of photovoltaic output can cause the voltage fluctuation of a common connection point of a photovoltaic system to be large, and adverse effects are brought to the normal operation of the power distribution network.
The traditional adjusting mode is generally adopted for voltage control of the existing power distribution network, and comprises capacitor reactive compensation, tap change of a regulating transformer and the like, and the devices are operated through switches, so that not only is the maintenance cost high, but also discrete adjustment of power can only be realized.
The problem solved by utilizing a distributed power supply to control voltage in the prior art is generally that the voltage of a grid-connected point and an access point is out of limit, and the control objects are a photovoltaic inverter and traditional switch type equipment, and the method mainly comprises the following steps:
(1) calculating voltage-active/reactive sensitivity
The voltage-real/reactive sensitivity is derived from the voltage drop formula, ignoring line losses and voltage variations, as shown in formula (1).
Wherein,
and
voltage-active and voltage-reactive sensitivities, W, respectively, of the voltage at node m relative to the active and reactive changes at node nmFor a set of lines and nodes from node 0 to node m, WnBeing a collection of lines and nodes from node 0 to node n, RiAnd XiFor the resistance and reactance value of line i, Ui-1Is the voltage at node i-1 (node 0 is the balanced node, and the voltage amplitude and phase are constant).
(2) Determining a voltage adjustment matrix, Uneed＝[Uneed1Uneed2...Uneedn]，
Wherein, UneedThe voltage adjustment amount for each node is positive or negative.
(3) Aiming at each voltage out-of-limit node, the nodes are arranged from large to small according to the sensitivity and are sequentially adjusted, the adjustment amount is determined by the sensitivity and the voltage demand, and the power adjustment amount of the nodes is calculated as shown in a formula (2).
Wherein, Δ P and Δ Q are the total amount of active and reactive power adjustment required by each node, respectively, and since the voltage adjustment amount has positive or negative, the power adjustment amount also has positive or negative.
(4) The final adjustment amount of each node is the maximum value of the adjustment amounts calculated by all nodes.
(5) And (4) continuously repeating the steps (2) to (4) until all the voltages meet the requirements.
Different from a high-voltage transmission line, the resistance of the distribution line is far larger than the reactance parameter, so that the influence of active adjustment on voltage is larger than that of reactive adjustment, and the response speed is higher. When the voltage is too high, the energy utilization rate of photovoltaic power generation is reduced by reducing the photovoltaic output, and the economical efficiency of active power adjustment can be effectively improved by considering that the energy storage device can provide short-time high-power injection or extraction. Meanwhile, the reactive power adjusting capability of the inverter can adjust the voltage to a certain degree.
However, the photovoltaic inverter only controls the voltage of the grid-connected point, the problem that the voltage at the public connection point is out of limit cannot be solved, and the photovoltaic inverter is only used for controlling the voltage, so that the reduction of active power reduces the energy utilization rate, and the adjustment of reactive power is limited. Meanwhile, the three-phase imbalance problem of the public connection point is not considered in the control method, most of household low-voltage photovoltaic devices are single-phase grid-connected devices, and the three-phase imbalance problem can be aggravated by blind adjustment.
Disclosure of Invention
The invention realizes the continuous control of the voltage of the common connection point by coordinately controlling the active power and the reactive power of the photovoltaic inverter and the energy storage device (hereinafter referred to as photovoltaic and energy storage). The active absorption of the energy storage device replaces the active reduction of the photovoltaic inverter, so that the new energy consumption is ensured; the reactive power adjustment of the energy storage device equivalently increases the reactive power adjustment capability of the photovoltaic inverter. And considering that the charging of the stored energy to the power grid actively relates to the charging problem of the power market, the adjusting sequence of the device in the voltage boosting and reducing measures is different. Meanwhile, reactive power adjustment margin is improved, split-phase adjustment is carried out on power according to the unbalanced condition of three-phase power of a public connection point, the problem of three-phase imbalance can be improved simultaneously, and the electric energy quality is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a photovoltaic system common connection point voltage control method considering three-phase unbalance comprises the following steps: calculating the voltage deviation of the public connection point of each node, and judging whether the voltage deviation of the public connection point meets the voltage deviation standard or not; if the voltage deviation is larger than the maximum voltage deviation standard, voltage reduction processing is carried out through the photovoltaic inverter and/or the energy storage device, and if the voltage deviation is smaller than the minimum voltage deviation standard, voltage boosting processing is carried out through the photovoltaic inverter and/or the energy storage device.
Preferably, in the step-down processing, the voltage of the common connection point is stepped down in the order of active adjustment of the energy storage device, reactive adjustment of the photovoltaic inverter, and active adjustment of the photovoltaic inverter.
Preferably, in the boosting process, the voltage of the common connection point is boosted in the order of reactive power adjustment of the energy storage device, reactive power adjustment of the photovoltaic inverter and active power adjustment of the energy storage device.
Preferably, in the process of performing the voltage reduction processing and/or the voltage boost processing, the required active adjustment amount of the photovoltaic inverter and/or the energy storage device at each node is obtained according to the active adjustment margin and the required active adjustment total amount of each node, and
and obtaining the required reactive power adjustment quantity of the photovoltaic inverter and/or the energy storage device at each node through a voltage adjustment formula according to the reactive power adjustment margin and the required reactive power adjustment total quantity of each node.
Preferably, the split-phase power adjustment is performed on the photovoltaic inverter and/or the energy storage device during the step-down process and/or the step-up process.
Preferably, in the split-phase power adjustment step of each active adjustment and reactive adjustment of the photovoltaic inverter and the energy storage device, it is respectively determined whether an active amount or a reactive amount required to be adjusted for each phase exceeds an active adjustment margin or a reactive adjustment margin, if not, a required active adjustment amount or a required reactive adjustment amount of each node is obtained through a voltage adjustment formula, if so, a required active adjustment amount or a required reactive adjustment amount of each node is calculated without exceeding a communicating overvoltage adjustment formula, and the excess phase is adjusted according to the maximum margin.
Preferably, during the step-down processing and/or the step-up processing, after the split-phase power adjustment is performed on the photovoltaic inverter and/or the energy storage device, the non-split-phase power adjustment is further performed on the photovoltaic inverter and/or the energy storage device.
Preferably, in the step of adjusting the non-split-phase power of each active adjustment and reactive adjustment of the photovoltaic inverter and the energy storage device, whether the total active amount or total reactive amount of three phases to be adjusted exceeds a total active adjustment margin or a total reactive adjustment margin of three phases is respectively determined, if not, the total active amount or total reactive amount of three phases to be adjusted of each node is obtained through a voltage adjustment formula, and if so, the adjustment is performed according to a maximum margin.
Preferably, one or more of the reactive power, the active amount still to be adjusted and the reactive amount still to be adjusted at the point of common connection of the nodes are updated during the step-down process and/or the step-up process.
Compared with the prior art, the invention has the following advantages and beneficial effects:
the research object of the invention is a common connection point, which ensures that the voltage of the common connection point meets the requirement and improves the power quality to a certain extent; the controlled objects of the invention are a photovoltaic inverter and an energy storage device, which can realize continuous adjustment of power and improve the problems of reduced energy utilization rate and limited photovoltaic reactive power adjustment capability caused by reduction of photovoltaic active power.
The invention adopts different adjustment sequences according to different voltage out-of-limit conditions and by combining practical conditions. In the voltage reduction measure, the active power adjustment is more effective, and the reduction of the photovoltaic active power can reduce the energy utilization rate, so that the energy storage active power is preferentially adjusted, and then the energy storage reactive power, the photovoltaic reactive power and the photovoltaic active power are adjusted; in the step-up measure, because it is unrealistic to increase photovoltaic active power output, the energy storage is fed into the electric wire netting actively and is related to the charging problem, therefore priority adjustment energy storage is idle, secondly photovoltaic is idle, the energy storage is active. The invention considers the charging problem in practice, and adopts different adjusting sequences aiming at different voltage conditions.
The invention carries out split-phase adjustment on the power of each node, regulates the voltage and simultaneously considers three-phase imbalance, and is beneficial to better improving the quality of electric energy.
Drawings
FIG. 1 is a schematic diagram of a point-of-presence, access point, and point of common connection for a power distribution network;
FIG. 2 is a flow chart of the buck-boost process of the present invention;
FIG. 3 is a flow chart of split phase power adjustment of the present invention;
fig. 4 is a flow chart of non-phased power adjustment in accordance with the present invention.
Detailed Description
The present invention will now be described in further detail with reference to the attached figures, so that the invention will be more clearly and easily understood. Those of ordinary skill in the art will recognize that the described embodiments can be modified in various different ways, or combinations thereof, without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. Furthermore, in the present description, the drawings are not to scale and like reference numerals refer to like parts.
First, some technical terms in the present invention are explained with reference to fig. 1.
And (3) grid connection point: for a distributed power supply with a booster station, a grid-connected point is a high-voltage side bus or node of the booster station of the distributed power supply; for a distributed power supply without a booster station, the grid-connected point is an output summary point of the distributed power supply. Points a1 and B1 are the grid-connected points of the distributed power source A, B, respectively, as shown in fig. 1. Point C1 is the point of connection of conventional power supply C.
An access point: refers to the connection of a power source into a power grid, which may be either a public power grid or a consumer power grid. Points a2 and B2 are access points of the distributed power source A, B, and point C2 is an access point of the conventional power source C, respectively.
Common connection point: refers to the connection of the customer system (generating or using electricity) to the utility grid. As shown in FIG. 1, points C2 and D are both common connection points, and points A2 and B2 are not common connection points.
An embodiment of the present invention is described in detail below with reference to fig. 2-4.
The voltage control method of the photovoltaic system common connection point comprises the following steps:
s1: according to the voltage of the public connection point of each node of the regional power distribution network, the voltage deviation of the public connection point is calculated, and whether the voltage of the public connection point meets the voltage deviation standard (for example, the 10kV voltage deviation in China is allowed to be + 7%, -7%) is judged. And,
calculating the voltage deviation of the common connection point as shown in a formula (3), and if the voltage deviation delta U is larger than the maximum voltage deviation standard (such as + 7%), performing voltage reduction treatment subsequently; if the voltage deviation delta U is smaller than the minimum voltage deviation standard (such as-7%), performing boosting treatment subsequently;
wherein U isPCCIs the effective value (calculated by three-phase voltage) of the voltage of the common connection point, UNThe rated value (380V, the rated value is 380V because the measurement and control device of the photovoltaic system is assumed to be installed on the low-voltage side of the 10kV/380V transformer) is the effective value of the voltage of the public connection point, and the delta U is the voltage deviation of the public connection point.
S2: according to the voltage and current of a public connection point of each node of a regional power distribution network and energy storage and photovoltaic adjustment margins, voltage boosting and reducing processing is carried out, if the voltage deviation is larger than a voltage deviation standard, voltage reducing processing is carried out according to the sequence of energy storage active power, energy storage reactive power, photovoltaic reactive power and photovoltaic active power, if the voltage deviation is smaller than the voltage deviation standard, voltage boosting processing is carried out according to the sequence of energy storage reactive power, photovoltaic reactive power and energy storage active power, the total adjustment amount of each phase is determined by considering the three-phase balance degree in the adjustment process, and the photovoltaic and energy storage adjustment amount of each node is determined according to a voltage adjustment formula.
The following preparation steps are first performed.
And calculating the active power and reactive power adjustment margin of each node of the regional power distribution network. Calculating an active margin according to the active limit and real-time active of each node, as shown in a formula (4);
ΔPmax＝|Plimit-P| (4)
wherein, PlimitIs the upper limit/lower limit of active power output of each node, P is the real-time active power of each node, delta PmaxAn active margin (when the node output power is positive and the absorbed power is negative, the active margin is calculated, if the absorbed power is increased or the output is reduced, the lower limit of the output is used, and if the output is increased, the upper limit of the output is used);
calculating reactive margin according to the reactive limit and the real-time reactive of each node, as shown in a formula (5);
ΔQmax＝|Qlimit-Q| (5)
wherein Q islimitFor the upper limit/lower limit of reactive output of each node, Q is the real-time active power of each node, Delta QmaxThe reactive margin is obtained (when the reactive margin is calculated, the lower output limit is used if the absorption amount is increased, and the upper output limit is used if the output amount is increased).
Wherein, the voltage adjustment formula is shown as the following formula (6);
wherein Δ PiAnd Δ QiRespectively the active and reactive adjustment, delta P, of the stored energy or photovoltaic at node iimaxAnd Δ QimaxThe active and reactive margins of node i calculated in the above step S2, respectively, and Δ P and Δ Q are the total amount of required active and reactive adjustments calculated in the following steps, respectively.
Since Δ P and Δ Q do not take absolute values, they are electrically connectedThe pressure deviation is positive or negative, Δ P and Δ Q are also positive or negative, and Δ P is thusiAnd Δ QiAnd if the power of each node is positive or negative, the adjustment amount is directly added to real-time active power and reactive power when the power of each node is adjusted, whether the adjustment amount is increased or decreased is not considered, and whether the adjustment amount is increased or decreased is distinguished to determine whether the adjustment margin is calculated by using an upper limit or a lower limit of the output.
S21: step of depressurization treatment
S211, calculating active power P from voltage of common connection point and current of common connection pointA、PB、PCAnd determining the active power quantity delta P required to be adjusted for each phase according to the formulas (7) and (8)A、ΔPB、ΔPC；
PA+ΔPA＝PB+ΔPB＝PC+ΔPC(8)
Wherein R is the resistance from the balance node to the common connection point, power absorption is negative, output is positive, and U isPCCIs the voltage of the common connection point, UNTo balance the voltage at the node, Δ P may be positive or negative, such that Δ PA、ΔPB、ΔPCMay be positive or negative.
S212, whether energy can be stored continuously or not is determined according to the energy storage state of charge (SOC) of each node of the regional power distribution network, if the energy can be stored continuously, the power quantity required to be adjusted of each phase obtained in S211 is compared with the energy storage adjustment margin, if the power quantity required to be adjusted of each phase does not exceed the energy storage adjustment margin (the power quantities required to be adjusted of each phase are calculated by formulas (4) and (5), the energy storage is divided into three ABC phases, the power quantities of all the nodes of each phase are added, and then the comparison is carried out), the adjustment quantity required by each node is calculated according to the formula (6) in a split-phase mode, and the voltage regulation is finished; otherwise, the non-exceeding phase calculates the required adjustment amount according to equation (6), the exceeding phase is adjusted according to the maximum margin (i.e., the lower output limit), and step S213 is performed (here, taking the case of increasing the energy storage active absorption amount, so the lower active output limit is adopted when calculating the active margin in the above equation);
s213 is prepared fromReactive power Q calculated by public connection point voltage and public connection point currentA、QB、QCThe amount of reactive power Δ Q to be adjusted for each phase is determined by equations (9) and (10)A、ΔQB、ΔQC；
QA+ΔQA＝QB+ΔQB＝QC+ΔQC(10)
Where X is the reactance from the balance node to the common connection point, power absorption is negative, output is positive, UPCCIs the voltage of the common connection point, UNTo balance the voltage at the node, Δ Q may be positive or negative, such that Δ QA、ΔQB、ΔQCMay be positive or negative.
S214, if the reactive power required to be adjusted of each phase does not exceed the energy storage adjustment margin, the required adjustment amount is calculated according to the formula (6) in a split-phase mode, and the voltage regulation is finished; otherwise, the non-excess phase calculates the required adjustment amount according to equation (6), the excess phase is adjusted according to the maximum margin (i.e., the lower output limit), and step S215 is performed (here, taking the case where the amount of energy storage reactive power absorption is to be increased, so the lower reactive output limit is adopted when calculating the reactive margin in the above equation);
s215, updating reactive power Q of public connection pointA、QB、QCThe amount of reactive power Δ Q to be adjusted for each phase is determined by equations (9) and (10)A、ΔQB、ΔQC；
S216, if the reactive power required to be adjusted of each phase does not exceed the photovoltaic adjustment margin, calculating the required adjustment amount according to a formula (6), and ending voltage regulation; otherwise, the non-excess phase is adjusted according to equation (6), the excess phase is adjusted according to the maximum margin (i.e., the lower output limit), and step S217 is performed (here, taking the amount of the photovoltaic reactive absorption to be increased as an example, so the lower reactive output limit is adopted when calculating the reactive margin in the above equation);
s217, calculating voltage deviation according to a formula (3), and if the voltage deviation meets the requirement lower than the maximum voltage deviation standard, finishing voltage regulation; otherwise, go to step S218;
s218, updating the active total amount which still needs to be adjusted according to a formula (7), calculating the total adjustment margin of the energy storage active three phases, and if the active adjustment total amount does not exceed the total adjustment margin, calculating the adjustment amount according to a formula (6) for the adjustable node, wherein the adjustment amount does not distinguish A, B, C three phases; if the total active adjustment amount exceeds the total adjustment margin, adjusting according to the maximum margin (i.e. the lower output limit), and executing step S219 (taking the case of increasing the energy storage active absorption amount, so the lower active output limit is adopted when calculating the active margin in the above formula);
s219, updating the reactive total amount which still needs to be adjusted according to a formula (9), calculating the total energy storage reactive adjustment margin, and if the total reactive adjustment margin does not exceed the adjustment margin, calculating the adjustment amount according to a formula (6) for the adjustable energy storage nodes, wherein the adjustment amount does not distinguish A, B, C three phases; if the total reactive power adjustment amount exceeds the margin, adjusting according to the maximum margin (i.e. the lower output limit), and executing step S2110 (taking the case of increasing the reactive power absorption amount of the energy storage, so the lower reactive power limit is adopted when calculating the reactive power margin in the above formula);
s2110, updating the reactive total amount still needing to be adjusted according to a formula (9), calculating the photovoltaic reactive total adjustment margin, and if the reactive total amount does not exceed the adjustment margin, calculating the adjustment amount according to a formula (6) for the adjustable photovoltaic nodes, wherein the adjustment amount does not distinguish A, B, C three phases; if the total reactive power adjustment amount exceeds the margin, adjusting according to the maximum margin (i.e. the lower output limit), and executing step S2111 (taking the photovoltaic reactive power absorption amount to be increased as an example, so the lower reactive power output limit is adopted when calculating the reactive power margin in the above formula);
s2111, calculating voltage deviation according to a formula (3), and if the voltage deviation meets the requirement of being lower than the maximum voltage deviation standard, finishing voltage regulation; otherwise, calculating the active power of each phase still needing to be adjusted according to the formulas (7) and (8), if each phase does not exceed the adjustment margin, adjusting the photovoltaic reduction active power of each node according to the formula (6), and finishing voltage regulation; otherwise, the non-exceeding phase is adjusted according to the formula (6), the exceeding phase is adjusted according to the maximum margin, and the step S2112 is executed;
s2112, updating the active total quantity which still needs to be adjusted according to a formula (7), calculating the total adjustment margin of the photovoltaic active three phases, and if the active adjustment total quantity does not exceed the adjustment margin, calculating the adjustment quantity of the adjustable energy storage node according to a formula (6), wherein the adjustment quantity does not distinguish A, B, C three phases; if the total active adjustment amount exceeds the margin, the adjustment is performed according to the maximum margin (i.e. the lower output limit), and the voltage regulation is finished (taking the photovoltaic active output amount to be reduced as an example, so the lower active output limit is adopted when the reactive margin is calculated in the above formula).
Step of S22 pressure increasing processing
S221, calculating reactive power Q from voltage of common connection point and current of common connection pointA、QB、QCThe amount of reactive power Δ Q to be adjusted for each phase is determined by equations (9) and (10)A、ΔQB、ΔQC；
S222, if all phases do not exceed the energy storage adjustment margin, the required adjustment amount is calculated according to the formula (6) in a split-phase mode, and the voltage adjustment is finished; otherwise, the phase not exceeding is adjusted according to the formula (6), the phase exceeding is adjusted according to the maximum margin (i.e. the upper output limit), and step S223 is executed (here, taking the case of increasing the reactive output of the energy storage, so the upper reactive output limit is adopted when calculating the reactive margin in the above formula);
s223 updating public connection point reactive power QA、QB、QCThe amount of reactive power Δ Q to be adjusted for each phase is determined by equations (9) and (10)A、ΔQB、ΔQC；
S224, if the reactive power required to be adjusted of each phase does not exceed the photovoltaic adjustment margin, calculating the required adjustment amount according to a formula (6), and ending the voltage regulation; otherwise, the phase not exceeding is adjusted according to equation (6), the phase exceeding is adjusted according to the maximum margin (i.e., the upper output limit), and step S225 is executed (here, taking the case of increasing the photovoltaic reactive output, so the upper reactive output limit is adopted when calculating the reactive margin in the above equation);
s235 calculating active power P from the voltage of the common connection point and the current of the common connection pointA、PB、PCAnd determining the active power quantity delta P required to be adjusted for each phase according to the formulas (7) and (8)A、ΔPB、ΔPC；
S226, determining adjustable energy storage and adjustment margin according to the energy storage SOC state, if the active power required to be adjusted of each phase does not exceed the energy storage adjustment margin, performing split-phase calculation on the adjustment quantity required by each node according to a formula (6), and finishing voltage regulation; otherwise, the required adjustment amount is calculated according to the formula (6) for the non-exceeding phase, the exceeding phase is adjusted according to the maximum margin (i.e. the output upper limit), and step S227 is executed (taking the case of increasing the energy storage active output amount, so the active output upper limit is adopted when the active margin is calculated in the above formula);
s227, calculating voltage deviation according to a formula (3), and if the voltage deviation meets the standard requirement higher than the minimum voltage deviation, finishing voltage regulation; otherwise, go to step S228;
s228, the reactive total amount which still needs to be adjusted is updated according to the formula (9), the total energy storage reactive adjustment margin is calculated, if the reactive adjustment total amount does not exceed the adjustment margin, the adjustment amount is calculated according to the formula (6) for the adjustable energy storage nodes, and at the moment, the adjustment amount does not distinguish A, B, C three phases; if the total reactive power adjustment amount exceeds the margin, adjusting according to the maximum margin (i.e. the upper output limit), and executing step S229 (taking the case of increasing the reactive power output of the energy storage, so the upper reactive power output limit is adopted when calculating the reactive power margin in the above formula);
s229, the reactive total amount which still needs to be adjusted is updated according to the formula (9), the photovoltaic reactive total adjustment margin is calculated, if the reactive total amount does not exceed the adjustment margin, the adjustment amount is calculated for the adjustable photovoltaic nodes according to the formula (6), and at the moment, the adjustment amount does not distinguish A, B, C three phases; if the total reactive power adjustment amount exceeds the margin, adjusting according to the maximum margin (i.e. the upper output limit), and executing step S2210 (taking the photovoltaic reactive power output amount to be increased as an example, so the upper reactive power output limit is adopted when calculating the reactive power margin in the above formula);
s2210, updating the active total quantity still needing to be adjusted according to a formula (7), calculating the total adjustment margin of active three phases of the energy storage device, if the active adjustment total quantity does not exceed the adjustment margin, calculating the adjustment quantity of the adjustable energy storage node according to a formula (6), and at the moment, the adjustment quantity does not distinguish A, B, C three phases; if the total active power adjustment amount exceeds the margin, the adjustment is performed according to the maximum margin (i.e. the upper output limit), and the voltage regulation is finished (taking the case of increasing the active energy output amount of the energy storage, so the upper active power output limit is adopted when the active power margin is calculated in the above formula).
FIG. 3 is a flow chart of split phase power adjustment of the present invention, showing the flow of S211-S217 and S221-S227. FIG. 4 is a flow chart of non-phased power adjustment of the present invention, showing the flow of S218-S2112 and S228-S2210. And the non-phase-splitting power adjustment is to further adjust the voltage under the condition that the voltage is still unqualified after each device finishes phase-splitting power adjustment, and the power adjustment does not split phases at the moment.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A photovoltaic system common connection point voltage control method considering three-phase unbalance comprises the following steps:
s1: calculating the voltage deviation of the public connection point of each node, and judging whether the voltage deviation of the public connection point meets the voltage deviation standard or not;
s2: if the voltage deviation is larger than the maximum voltage deviation standard, the voltage is reduced through the photovoltaic inverter and/or the energy storage device, if the voltage deviation is smaller than the minimum voltage deviation standard, the voltage is increased through the photovoltaic inverter and/or the energy storage device,
during the voltage reduction and/or the voltage boosting, the required active adjustment quantity of the photovoltaic inverter and/or the energy storage device at each node is obtained through a voltage adjustment formula according to the active adjustment margin and the required active adjustment total quantity of each node, and
obtaining the required reactive power adjustment quantity of the photovoltaic inverter and/or the energy storage device at each node through the voltage adjustment formula according to the reactive power adjustment margin and the required reactive power adjustment total quantity of each node,
wherein, the voltage regulation formula is as follows:
wherein, Δ PiAnd Δ QiRespectively, a required active adjustment quantity and a required reactive adjustment quantity, delta P, of the photovoltaic inverter and/or the energy storage device at the ith nodeimaxAnd Δ QimaxRespectively are the active adjustment margin and the reactive adjustment margin at the ith node, Δ P and Δ Q are the total amount of the required active adjustment and the total amount of the required reactive adjustment, m is the total number of the nodes, and i is a natural number greater than zero and less than or equal to m.
2. The voltage control method according to claim 1, wherein, during the step-down process, the voltage of the point of common connection is stepped down in the order of energy storage device active adjustment, energy storage device reactive adjustment, photovoltaic inverter active adjustment.
3. The voltage control method according to claim 1, wherein the voltage at the common connection point is boosted in the order of energy storage device reactive power regulation, photovoltaic inverter reactive power regulation, and energy storage device active power regulation during the boosting process.
4. The voltage control method according to claim 1, wherein the split-phase power adjustment is performed on the photovoltaic inverter and/or the energy storage device during the step-down process and/or the step-up process.
5. The voltage control method according to claim 4, wherein in the split-phase power adjustment steps of active adjustment and reactive adjustment of the photovoltaic inverter and the energy storage device, whether the active amount or the reactive amount required to be adjusted for each phase exceeds an active adjustment margin or a reactive adjustment margin is respectively judged, if not, the required active adjustment amount or the required reactive adjustment amount of each node is obtained through a voltage adjustment formula, if not, the required active adjustment amount or the required reactive adjustment amount of each node is calculated without exceeding a phase connection overvoltage adjustment formula, and the excess phase is adjusted according to the maximum margin.
6. The voltage control method according to claim 4, wherein during the step-down process and/or the step-up process, after the split-phase power adjustment of the photovoltaic inverter and/or the energy storage device, the non-split-phase power adjustment of the photovoltaic inverter and/or the energy storage device is further performed.
7. The voltage control method according to claim 6, wherein in the step of adjusting the non-split-phase power of each active adjustment and reactive adjustment of the photovoltaic inverter and the energy storage device, whether the total active amount or total reactive amount of three phases to be adjusted exceeds a total active adjustment margin or a total reactive adjustment margin of three phases is respectively determined, if not, the total active amount or total reactive amount of three phases to be adjusted of each node is obtained through a voltage adjustment formula, and if so, the adjustment is performed according to a maximum margin.
8. The voltage control method according to claim 1, wherein one or more of the reactive power, the active amount that still needs to be adjusted, and the reactive amount that still needs to be adjusted at the common connection point of the nodes are updated during the step-down process and/or the step-up process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711350422.1A CN108183501B (en) | 2017-12-15 | 2017-12-15 | Photovoltaic system common connection point voltage control method considering three-phase imbalance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711350422.1A CN108183501B (en) | 2017-12-15 | 2017-12-15 | Photovoltaic system common connection point voltage control method considering three-phase imbalance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108183501A CN108183501A (en) | 2018-06-19 |
| CN108183501B true CN108183501B (en) | 2020-03-06 |
Family
ID=62546094
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711350422.1A Active CN108183501B (en) | 2017-12-15 | 2017-12-15 | Photovoltaic system common connection point voltage control method considering three-phase imbalance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108183501B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113824159A (en) * | 2021-09-14 | 2021-12-21 | 中腾微网（北京）科技有限公司 | Adaptive control microgrid reactive power regulation method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414196A (en) * | 2013-07-16 | 2013-11-27 | 中国科学院电工研究所 | Grid-connected inverter grid-connection point voltage dynamic compensation control method |
| CN104538988A (en) * | 2015-01-08 | 2015-04-22 | 广西大学 | Voltage stability regulating system for distributed power connection and control method thereof |
| CN105262149A (en) * | 2015-11-26 | 2016-01-20 | 阳光电源股份有限公司 | Method and system for inhibiting voltage fluctuation of photovoltaic power station |
| CN106300375A (en) * | 2015-05-16 | 2017-01-04 | 邵阳学院 | A kind of novel D-STATCOM voltage control method |
| CN106941257A (en) * | 2016-01-05 | 2017-07-11 | 许昌学院 | A kind of combining inverter compensating control method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014056633A1 (en) * | 2012-10-12 | 2014-04-17 | Siemens Aktiengesellschaft | Method and controller for continuously operating a plurality of electric energy generating machines during a high voltage condition |
-
2017
- 2017-12-15 CN CN201711350422.1A patent/CN108183501B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103414196A (en) * | 2013-07-16 | 2013-11-27 | 中国科学院电工研究所 | Grid-connected inverter grid-connection point voltage dynamic compensation control method |
| CN104538988A (en) * | 2015-01-08 | 2015-04-22 | 广西大学 | Voltage stability regulating system for distributed power connection and control method thereof |
| CN106300375A (en) * | 2015-05-16 | 2017-01-04 | 邵阳学院 | A kind of novel D-STATCOM voltage control method |
| CN105262149A (en) * | 2015-11-26 | 2016-01-20 | 阳光电源股份有限公司 | Method and system for inhibiting voltage fluctuation of photovoltaic power station |
| CN106941257A (en) * | 2016-01-05 | 2017-07-11 | 许昌学院 | A kind of combining inverter compensating control method |
Non-Patent Citations (1)
| Title |
|---|
| 光伏并网发电***中公共连接点的电压调节;徐杰等;《科学技术与工程》;20130430;第13卷(第11期);第2970-2975页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108183501A (en) | 2018-06-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109802396B (en) | Photovoltaic transformer area electric energy quality control system based on voltage sensitivity configuration | |
| CN111244931B (en) | SOC self-balancing control method for parallel operation of multiple energy storage modules | |
| CN109004653B (en) | Method for treating rural power grid overvoltage caused by photovoltaic access through active and reactive coupling | |
| CN104158169B (en) | A kind of photovoltaic DC microgrid busbar voltage control method | |
| CN107968417A (en) | A kind of three-phase two-stage type photovoltaic system participates in the control method for coordinating that mains frequency is adjusted | |
| CN105183999B (en) | Electric system maximum short circuit current computational methods containing photovoltaic plant | |
| CN104578086A (en) | Reactive voltage control method of wind power and photovoltaic power generation access grid | |
| CN104810822A (en) | Control method of micro-grid bidirectional DC/DC (Direct Current/Direct Current) change drooping coefficient | |
| CN108711868A (en) | It is a kind of meter and islet operation voltage security GA for reactive power optimization planing method | |
| CN105703374A (en) | New-type urbanization-based low voltage treatment measures optimization method | |
| CN104638668A (en) | Photovoltaic power generation grid connection control method and photovoltaic power generation grid connection control system | |
| CN105529720A (en) | Dynamic reactive power priority based automatic switching method of capacitor of wind power plant | |
| CN112332421A (en) | Photovoltaic power station participation power grid voltage regulation method based on adaptive droop control | |
| CN105226716A (en) | A kind of distributed double-fed wind power generator group automatic voltage control method | |
| CN110350538B (en) | Micro-grid coordination control method based on active demand side response | |
| CN110112723B (en) | Droop control method for DC micro-grid in off-grid state | |
| CN108183501B (en) | Photovoltaic system common connection point voltage control method considering three-phase imbalance | |
| CN113725921B (en) | Control method for participating in grid frequency modulation at left side of maximum power point in photovoltaic operation | |
| CN108376997B (en) | Active power distribution network island division method considering distributed power supply uncertainty | |
| CN111799812B (en) | Reactive voltage sensitivity-based reactive coordination control method for offshore wind farm | |
| CN105680463B (en) | Optimal energy-saving control method for light storage integrated power generation system | |
| CN106451477A (en) | Reactive power voltage coordination control method adaptable to clustered wind-solar-electricity access system | |
| CN113742907B (en) | Unified calculation method for short-circuit current of photovoltaic power station | |
| CN115663780A (en) | Improved self-adaptive subsection droop control method for photovoltaic direct-current micro-grid | |
| CN115313347A (en) | Transient state self-adaptive virtual inertia control method for storage battery in direct-current micro-grid |
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 |