Three-phase imbalance treatment method and micro-energy regulator

Abstract

The invention relates to a three-phase imbalance treatment method and a micro-energy regulator, and belongs to the technical field of power supply systems. The method comprises the steps that when a three-phase imbalance phenomenon occurs, the three-phase imbalance degree is obtained according to the maximum power deviation between phases and the total power of the three phases; when the three-phase unbalance degree is greater than a preset unbalance degree, calculating the single-phase power deviation of each phase according to the three-phase average power and the single-phase power of each phase; comparing the three-phase total power with a preset transformer area load rate, and when the three-phase total power is greater than the preset transformer area load rate, storing energy and discharging; if yes, the single-phase power deviation needs to be updated according to corresponding design requirements; for energy storage, the total discharge power or the total power absorption power of each phase is determined according to the updated single-phase power deviation, proportional gain and integral gain; and discharging or absorbing electricity for each phase until the total discharging power or the total electricity absorbing power of each phase is met. According to the invention, the phenomenon of heavy load or return of the transformer area can be reduced.

Description

Technical Field

[0001] The invention relates to a three-phase imbalance control method and a micro energy regulator, belonging to the technical field of power supply systems. Background Art

[0002] To achieve the "dual carbon" goals, energy is the main battlefield and electricity is the main force. The latest data from the National Bureau of Statistics shows that in the first quarter of 2024, the national industrial capacity utilization rate above designated size was 73.6%. In April 2024, the National Energy Administration issued the "Notice on Promoting the Grid Connection and Dispatching of New Energy Storage" (hereinafter referred to as the "Notice"). The "Notice" proposed to standardize the management of new energy storage grid connection, optimize the dispatching and operation mechanism, give full play to the role of new energy storage, and support the construction of a new power system. New energy storage is an important technology and basic equipment for building a new power system, and an important support for achieving the goals of carbon peak and carbon neutrality. It is necessary to promote the diversified development of new energy storage technologies, move from pilot demonstration to large-scale commercial use, and help accelerate the construction of a new energy system.

[0003] With the rapid development of new energy sources such as wind power and solar energy, the impact of their intermittent and volatile nature on the security of the power grid has become increasingly prominent. At the same time, climate change factors and extreme weather have aggravated the impact on the planning, production and operation of the power system, and the problems of power supply and system balance will become more prominent. The need to build a new energy storage system to ensure energy security and stable operation of the energy system is becoming more urgent. The "Notice" points out that it is necessary to accurately grasp the functional positioning of new energy storage, combine the functional positioning of new energy storage with market requirements, further standardize the management of new energy storage grid connection, and continuously improve the new energy storage dispatching mechanism to strongly support the construction of new power systems. All regions are accelerating the layout of new energy storage industries, and while improving the grid connection services of new energy storage, they are promoting the use of new energy storage in a market-oriented manner.

[0004] Due to the large-scale integration of distributed energy storage into the power system, it is expected that energy storage can add other new functions while completing peak-to-valley shifting, so as to improve the power quality of the power system by utilizing energy storage and achieve the purpose of helping the new power system to operate stably.

[0005] At present, in the power system, three-phase power imbalance in the substation is a common occurrence. Three-phase imbalance is considered to be a fault-type event that is more harmful to the power grid equipment. Therefore, when three-phase imbalance occurs, it is necessary to manage it. The Chinese invention patent application with application publication number CN115833216A discloses a method for managing three-phase imbalance in low-voltage substations based on a flexible DC system. The method is applied to a flexible DC system, and the flexible DC system includes an energy storage device. When the three-phase load in the low-voltage substation is unbalanced, the flexible DC system supplies power to the phase with a higher load or absorbs electric energy from the phase with a lower load; when the energy storage device discharges to the lower limit value, the flexible DC system stops supplying power to the phase with a higher load and turns to absorb electric energy from the phase with a lower load; when the energy storage device is charged to the upper limit value, the flexible DC system stops absorbing electric energy from the phase with a lower load and turns to supply power to the phase with a higher load; the advantages of the present invention are: realizing the management of three-phase imbalance in the low-voltage substation, the control process is simple, and no phase change is required, thereby not affecting the continuity of power supply to users, improving the power supply quality and operation level of the distribution network, and reducing safety hazards.

[0006] However, this method does not take the load rate of the substation into consideration, which may easily cause substation overload or substation backflow. Summary of the invention

[0007] The purpose of the present invention is to provide a three-phase unbalance control method and a micro energy regulator to solve the problem of overloading or backflow in the area in the process of regulating the three-phase unbalance in the prior art.

[0008] To achieve the above object, the solution of the present invention includes:

[0009] A three-phase imbalance control method of the present invention comprises the following steps:

[0010] When three-phase imbalance occurs, the three-phase imbalance degree is obtained according to the maximum power deviation between phases and the total power of three phases;

[0011] When the three-phase unbalance is greater than the preset unbalance, the single-phase power deviation of each phase is calculated according to the three-phase average power and the single-phase power of each phase;

[0012] When the three-phase total power is greater than the preset area load rate, the single-phase power deviation greater than or equal to zero is updated to zero, and the single-phase power deviation less than zero is updated to its absolute value; the energy storage determines the total discharge power for each phase according to its updated single-phase power deviation, its previous accumulated deviation, proportional gain and integral gain; the energy storage discharges each phase until the total discharge power of each phase is met;

[0013] When the total three-phase power is less than the preset substation load rate, the single-phase power deviation that is less than or equal to zero is updated to zero, and the single-phase power deviation that is greater than zero is updated to itself; the energy storage determines the total power absorption for each phase based on its updated single-phase power deviation, its previous accumulated deviations, proportional gain and integral gain; the energy storage absorbs power from each phase until the total power absorption of each phase is met.

[0014] Furthermore, when the total power of the three phases is greater than the preset area load rate, the energy storage discharges each phase at one third of its rated discharge power;

[0015] When the total three-phase power is less than the preset station load rate, the energy storage absorbs electricity from each phase at one-third of its rated charging power.

[0016] Furthermore, during the process of discharging each phase of the energy storage, if the state of charge of the energy storage is less than a first preset state of charge, the discharging is stopped;

[0017] In the process of the energy storage absorbing electricity from each phase, if the charge state of the energy storage is greater than the second preset charge state, charging is stopped;

[0018] The second preset state of charge is greater than the first preset state of charge; and the sum of the first preset state of charge and the second preset state of charge is 100%.

[0019] Furthermore, the three-phase unbalance degree is a quotient obtained by dividing the maximum power deviation between phases by the total power of the three phases.

[0020] Furthermore, the maximum power deviation between phases and the corresponding three-phase total power are collected multiple times, and the quotient of the maximum power deviation between phases and the corresponding three-phase total power is calculated, and the average is used as the three-phase imbalance.

[0021] Furthermore, when the three-phase total power needs to be collected multiple times, the three-phase total power compared with the preset station area load rate is the average three-phase total power obtained after collecting the three-phase total power multiple times.

[0022] Furthermore, single-phase power deviation=three-phase average power-single-phase power.

[0023] Furthermore, the single-phase power deviation is calculated according to the control ratio parameter;

[0024] Single-phase power deviation = (three-phase average power - single-phase power) * control ratio parameter.

[0025] Furthermore, the energy storage adopts PI control to discharge or absorb electricity in each phase.

[0026] A micro energy regulator of the present invention comprises a processor, wherein the processor executes a computer program to implement the steps of the aforementioned three-phase unbalance control method.

[0027] The beneficial effects of the present invention are as follows: as a pioneering invention, the present invention provides a three-phase imbalance control method and a micro-energy regulator, which obtains the three-phase imbalance degree according to the maximum power deviation between phases and the three-phase total power when the three-phase imbalance occurs; when the three-phase imbalance degree is greater than the preset imbalance degree, the single-phase power deviation of each phase is calculated according to the three-phase average power and the single-phase power of each phase; when the three-phase total power is greater than the preset area load rate, the single-phase power deviation greater than or equal to zero is updated to zero, and the single-phase power deviation less than zero is updated to its absolute value. value; the energy storage determines the total discharge power for each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage discharges each phase until the total discharge power of each phase is met; when the three-phase total power is less than the preset station load rate, the single-phase power deviation that is less than or equal to zero is updated to zero, and the single-phase power deviation that is greater than zero is updated to itself; the energy storage determines the total power absorption for each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage absorbs power for each phase until the total power absorption of each phase is met. Since the single-phase power deviation is updated according to different situations while considering the station load rate, the total discharge power or total power absorption of the energy storage for each phase is determined by the updated single-phase power deviation, proportional gain and integral gain, which can make the energy storage more accurately regulate each phase and reduce the occurrence of station overload or station return. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a new energy power grid system provided by an embodiment of the present invention;

[0029] Figure 2 It is a flow chart of a three-phase imbalance control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] The concept of the present invention is: when the total power of the three phases is greater than the preset load rate of the station area, the energy storage is discharged, and when the total power of the three phases is less than the preset load rate of the station area, the energy storage is charged. The total discharge power and total power absorbed by the energy storage for each phase are limited by the single-phase power deviation, proportional gain and integral gain.

[0032] Specifically, when three-phase imbalance occurs, the three-phase imbalance degree is obtained according to the maximum power deviation between phases and the total power of the three phases; when the three-phase imbalance degree is greater than the preset imbalance degree, the single-phase power deviation of each phase is calculated according to the three-phase average power and the single-phase power of each phase; when the total power of the three phases is greater than the preset station load rate, the single-phase power deviation greater than or equal to zero is updated to zero, and the single-phase power deviation less than zero is updated to its absolute value; the energy storage determines the total discharge power of each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage discharges each phase until the total discharge power of each phase is met; when the total power of the three phases is less than the preset station load rate, the single-phase power deviation less than or equal to zero is updated to zero, and the single-phase power deviation greater than zero is updated to itself; the energy storage determines the total power absorption of each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage absorbs power from each phase until the total power absorption of each phase is met. While taking the load rate of the substation into consideration, the single-phase power deviation is updated according to different situations. The total discharge power or total power absorption power of the energy storage for each phase is determined by the updated single-phase power deviation, proportional gain and integral gain. This allows the energy storage to more accurately control each phase and reduce the occurrence of substation overload or substation backfeed.

[0033] An embodiment of a three-phase imbalance control method:

[0034] A three-phase imbalance control method provided in an embodiment of the present invention relies on a new energy grid system with energy storage, wherein the new energy grid system can refer to Figure 1 . Figure 1 is a schematic diagram of a new energy power grid system provided by an embodiment of the present invention, such as Figure 1 As shown, the new energy grid system includes a transformer 10 , a main meter 20 , a micro energy controller 30 , a photovoltaic module 40 , an energy storage 50 and a residential load 60 .

[0035] Among them, the energy storage 50 is a power conversion system (PCS) with a single-phase decoupled output function, that is, when the energy storage is charged, the three phases can be charged at different charging powers without affecting each other, and when discharging, the three phases are discharged at different discharge powers. The energy storage 50 can only control the three phases to charge or discharge at the same time, and the maximum power of a single phase can be 0, and charging and discharging cannot coexist between different phases. The energy storage 50 includes a smart IoT meter 501, a battery management system 502, and an energy management system (EMS) 503 connected in series.

[0036] In order to achieve smooth control and avoid shocks to the power grid system caused by given mutations, thereby affecting the safe operation of the power grid system, the energy storage 50 may introduce PID control or PI control during the control process. The present invention does not specifically limit this. The following will take the introduction of PI control during the control process of the energy storage 50 as an example for illustrative explanation.

[0037] One end of the transformer 10 is connected to the substation 00, and the other end is respectively connected to the incoming end of the total meter 20, the incoming end of the micro energy controller 30, the photovoltaic component 40, the smart IoT meter 501 in the energy storage 50 and the resident load 60; the outgoing end of the total meter 20 is connected to the collection end of the micro energy controller 30; the control end of the micro energy controller 30 is respectively connected to the photovoltaic component 40, the EMS503 in the energy storage 50 and the resident load 60.

[0038] The resident load 60 includes adjustable loads and non-adjustable loads.

[0039] Among them, the micro energy controller 30 is an on-site management device for the entire substation power system, including a processor (not shown), which can collect voltage, current, power and other information from the substation outlet meter 20, and run certain algorithm logic to control the charging and discharging of the energy storage 50, control the controllable load, control the power generation of photovoltaic equipment, etc.

[0040] Among them, the algorithm logic includes a three-phase unbalanced governance algorithm, a substation overload governance algorithm, and a substation return governance algorithm, etc. The present invention does not make any special limitations on this. Since the three-phase unbalanced phenomenon is the most harmful to the power grid system, the three-phase unbalanced governance algorithm has the highest priority.

[0041] Combine the following Figure 2 The method steps of the processor in the micro energy controller 30 for controlling the three-phase unbalance phenomenon are described in detail.

[0042] Figure 2 FIG. 1 is a flow chart of a method for treating three-phase imbalance provided by an embodiment of the present invention. Figure 2 As shown, the treatment method includes the following steps S101 to S110.

[0043] S101. When a three-phase imbalance occurs, a three-phase imbalance degree Pdex is obtained according to a maximum power deviation Perr between phases and a three-phase total power Pall.

[0044] Specifically, the three-phase imbalance degree Pdex can be obtained by the following formula (1).

[0045]

[0046] The maximum power deviation Perr between phases can be determined by the following formula (2).

[0047] Perr=max(|Pa-Pb|, |Pc-Pb|, |Pa-Pc|) (2)

[0048] Among them, Pa represents the single-phase power of phase a, Pb represents the single-phase power of phase b, and Pc represents the single-phase power of phase c.

[0049] The single-phase power Pa of phase a, the single-phase power Pb of phase b, and the single-phase power Pc of phase c can be obtained by the following formulas (3), (4), and (5), respectively.

[0050] Pa=Ua*Ia*cosa (3)

[0051] Pb=Ub*Ib*cosb (4)

[0052] Pc=Uc*Ic*cosc (5)

[0053] Among them, Ua represents the voltage of phase a, Ub represents the voltage of phase b, Uc represents the voltage of phase c, Ia represents the current of phase a, Ib represents the current of phase b, Ic represents the current of phase c, cosa represents the power factor of phase a, cosb represents the power factor of phase b, and cosc ​​represents the power factor of phase c.

[0054] The voltages of phases a, b and c can be collected separately through a voltage transformer or a voltage sensor, etc.; the currents of phases a, b and c can be collected separately through a current transformer or a current sensor, etc.; the power factors of phases a, b and c can be collected separately through a transmitter-type power factor meter.

[0055] The three-phase total power Pall can be determined by the following formula (6).

[0056] Pall=Pa+Pb+Pc (6)

[0057] In order to prevent misjudgment, as an optional implementation method, the maximum power deviation Perr between phases can be collected multiple times, the three-phase total power Pall can be collected multiple times, the three-phase imbalance is calculated once after each collection, and the average value of the three-phase imbalance calculated multiple times is taken as the three-phase imbalance Pdex, and the average value of the three-phase total power collected multiple times is taken as the three-phase total power Pall.

[0058] Among them, the number of collection times for collecting the largest power deviation Perr between phases is the same as the number of collection times for collecting the three-phase total power Pall; the setting of the number of collection times can be set according to actual needs, and the present invention does not make any special limitation on this. The following illustrative explanation is given by taking the number of collection times of 6 as an example.

[0059] As an optional implementation, the collected data may be filtered to obtain data without interference, so as to improve the accuracy of subsequent judgments.

[0060] When collecting data six times as an example, the three-phase imbalance degree Pdex can be expressed by the following formula (7), and the three-phase total power Pall can be expressed by the following formula (8).

[0061]

[0062] Wherein, Pdex1 represents the first three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr1 collected for the first time and the three-phase total power Pall1 collected for the first time; Pdex2 represents the second three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr2 collected for the second time and the three-phase total power Pall2 collected for the second time; Pdex3 represents the third three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr3 collected for the third time and the three-phase total power Pall3 collected for the third time degree; Pdex4 represents the third degree of three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr4 collected for the fourth time and the total three-phase power Pall4 collected for the fourth time; Pdex5 represents the fifth degree of three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr5 collected for the fifth time and the total three-phase power Pall5 collected for the fifth time; Pdex6 represents the sixth degree of three-phase imbalance calculated by formula (1) based on the maximum phase-to-phase power deviation Perr6 collected for the sixth time and the total three-phase power Pall6 collected for the sixth time.

[0063] Among them, Pall1 represents the three-phase total power collected for the first time; Pall2 represents the three-phase total power collected for the second time; Pall3 represents the three-phase total power collected for the third time; Pall4 represents the three-phase total power collected for the fourth time; Pall5 represents the three-phase total power collected for the fifth time; Pall6 represents the three-phase total power collected for the sixth time.

[0064] S102, determine whether the three-phase imbalance degree Pdex is greater than a preset imbalance degree, if so, execute step S103; if less than or equal to, continue to execute step S101.

[0065] Among them, the preset imbalance is the condition for triggering three-phase imbalance control. When the three-phase imbalance Pdex is greater than the preset imbalance, the control is triggered and the three-phase imbalance is controlled. When the three-phase imbalance Pdex is less than or equal to the preset imbalance, the three-phase imbalance is not controlled. The numerical setting of the preset imbalance can be set according to actual conditions. The present invention does not make any special limitation on this. Those skilled in the art know that the smaller the preset imbalance is set, the earlier the three-phase imbalance can be controlled and the earlier the power grid system can be repaired. The preset imbalance of 0.15 is taken as an example for exemplary description, that is, when the three-phase imbalance Pdex is greater than 0.15, step S103 is executed, and when the three-phase imbalance is less than or equal to 0.15, step S101 is continued.

[0066] S103, calculating the single-phase power deviation Pierr of each phase according to the three-phase average power Pave and the single-phase power Pi of each phase.

[0067] Among them, i can be a, b and c, representing phase a, phase b and phase c respectively.

[0068] Specifically, the single-phase power deviation Paerr of phase a, the single-phase power deviation Pberr of phase b, and the single-phase power deviation Pcerr of phase c can be obtained according to the following formulas (9), (10), and (11), respectively.

[0069] Paerr=Pave-Pa (9)

[0070] Pberr=Pave-Pb (10)

[0071] Pcerr=Pave-Pc (11)

[0072] For more precise control, the single-phase power deviation Pierr can also be calculated according to the control ratio parameter K. Specifically, the single-phase power deviation Paerr of phase a, the single-phase power deviation Pberr of phase b, and the single-phase power deviation Pcerr of phase c can be obtained respectively by the following formulas (12), (13), and (14).

[0073] Paerr=(Pave-Pa)*K (12)

[0074] Pberr=(Pave-Pb)*K (13)

[0075] Pcerr=(Pave-Pc)*K (14)

[0076] The K value can be set according to actual needs, and can be 0.9, 1.0, 1.1, etc. The present invention does not specifically limit this. The following explanation will be given by taking K as 0.9 as an example.

[0077] Among them, the three-phase average power Pave can be obtained by the following formula (15).

[0078]

[0079] S104, determine whether the three-phase total power Pall is greater than the preset area load rate T, if greater, execute steps S105 to S107; if less, execute steps S108 to S110; if equal, continue to execute step S103.

[0080] Among them, the preset area load rate is set to prevent the area from being overloaded or returned during the treatment process. After the three-phase imbalance treatment is completed, the area load rate can be maintained consistent with the preset area load rate. The value of the preset area load rate can be set according to actual needs, but it must be less than the load rate when the area is overloaded in actual applications. The present invention does not make any special restrictions on this. The following takes the preset area load rate T as 30% of the total area load to the total area capacity as an example for exemplary explanation.

[0081] Taking the example that the substation load rate T is 30% of the total substation load to the total substation capacity, the substation load rate T can be obtained according to the following formula (16).

[0082] T=TCQN*0.3 (16)

[0083] Among them, TCQN represents the total capacity of the substation.

[0084] That is, when the three-phase total power Pall is greater than TCQN*0.3, execute steps S105 to S107; when the three-phase total power Pall is less than TCQN*0.3, execute steps S108 to S111; when the three-phase total power Pall is equal to TCQN*0.3, continue to execute step S103.

[0085] S105: Update the single-phase power deviation that is greater than or equal to zero to zero, and update the single-phase power deviation that is less than zero to its absolute value.

[0086] Among them, when the three-phase total power Pall is greater than the preset area load rate T, the energy storage 50 needs to discharge to offset part of the area load and balance the line pressure of the high-load phase, so that the three-phase total power Pall can be equal to the preset area load rate T. Before the energy storage is discharged, the single-phase power of each phase needs to be updated to prevent the energy storage 50 from discharging too much or too little to a certain phase, so as to accurately store the discharge amount.

[0087] Among them, a single-phase power deviation whose difference is greater than or equal to zero indicates that the actual power of the phase is relatively small, and the energy storage 50 does not need to discharge the phase. Therefore, the single-phase power deviation of the phase is updated to zero; a single-phase power deviation whose difference is less than zero indicates that the actual power of the phase is relatively large, and the energy storage 50 needs to discharge the phase to reduce the power of the phase. Therefore, the single-phase power deviation of the phase needs to be updated to its absolute value.

[0088] S106 , the energy storage 50 determines the total discharge power for each phase according to the updated single-phase power deviation, the accumulated deviations, the proportional gain KP and the integral gain KI.

[0089] Among them, the total discharge power Paout of phase a can be obtained by the following formulas (17), (18) and (19) respectively: 放 , total discharge power of phase b Pbout 放 And the total discharge power of phase c Pcout 放 .

[0090] Paout 放 = updated single-phase power deviation of phase a*KP+accumulated deviation of phase a*KI (17)

[0091] Pbout 放 = updated single-phase power deviation of phase b*KP+accumulated deviation of phase b*KI (18)

[0092] Pcout 放 = updated single-phase power deviation of phase c*KP+accumulated deviation of phase c*KI (19)

[0093] Among them, the settings of the values ​​of the proportional gain KP and the integral gain KI can be set according to actual conditions, and the present invention does not make any special limitation on this. The following illustrative description is given by taking the proportional gain KP as 0.8 and the integral gain KI as 0.3 as an example.

[0094] S107 , the energy storage 50 discharges each phase until the total discharge power of each phase is met.

[0095] The discharge power of the energy storage 50 for each phase is subject to the rated discharge power Pj of the energy storage 50. 放The purpose of the invention is to reduce the damage to the energy storage 50 and to increase the service life of the energy storage 50.

[0096] In order to ensure the balance of discharge for each phase, the energy storage 50 discharges according to its rated discharge power Pj 放 One third of the power is discharged to each phase until the total discharge power of each phase is met.

[0097] Those skilled in the art should know that if there is a phase with an updated single-phase power deviation of zero, its total discharge power will also be zero, and the energy storage 50 does not need to discharge this phase. It only needs to discharge other phases whose total discharge power is not zero at one third of their rated power discharge power until the total discharge power of the phase is met.

[0098] During the discharge process, in order to prevent the charge state of the energy storage 50 from being too low, continued discharge of the energy storage 50 will cause damage to the energy storage 50. As an optional implementation, the charge state of the energy storage 50 is detected in real time. If the charge state of the energy storage 50 is less than the first preset charge state, the discharge is stopped; if the charge state of the energy storage 50 is greater than or equal to the first preset charge state, the discharge continues.

[0099] S108. Update the single-phase power deviation that is less than or equal to zero to zero, and update the single-phase power deviation that is greater than zero to itself.

[0100] Among them, when the three-phase total power Pall is less than the preset area load rate T, the energy storage 50 needs to absorb electricity to consume part of the area load and balance the line current value of the low-load phase, so that the three-phase total power Pall can be equal to the preset area load rate T. Before the energy storage 50 absorbs electricity, the single-phase power of each phase needs to be updated to prevent the energy storage 50 from absorbing more or less from a certain phase, so as to accurately store the amount of energy absorbed.

[0101] Among them, if the difference is greater than the single-phase power deviation, it means that the actual power of the phase is relatively small, and the energy storage 50 needs to be added to the phase as an electrical device to increase the load rate of the phase. Therefore, the single-phase power deviation of the phase needs to be updated to itself. If the single-phase power deviation is less than or equal to zero, it means that the actual power of the phase is relatively large, and the energy storage 50 does not need to be added to the phase as an electrical device. Therefore, the single-phase power deviation of the phase is updated to zero.

[0102] S109. The energy storage 50 determines the total electric power absorbed by each phase according to the updated single-phase power deviation, the accumulated deviation, the proportional gain and the integral gain.

[0103] Among them, the total power absorption Paout of the energy storage 50 pairs of a phase can be obtained by the following formulas (20), (21) and (22) respectively:吸 , the total power absorption of phase b Pbout 吸 And the total power absorption of phase c Pcout 吸 .

[0104] Paout 吸 = updated single-phase power deviation of phase a*KP+accumulated deviation of phase a*KI (20)

[0105] Pbout 吸 = updated single-phase power deviation of phase b*KP+accumulated deviation of phase b*KI (21)

[0106] Pcout 吸 = updated single-phase power deviation of phase c*KP+accumulated deviation of phase c*KI (22)

[0107] S110 , the energy storage 50 absorbs electricity from each phase until the total electricity absorption power of each phase is met.

[0108] The power absorption of each phase by the energy storage 50 is subject to the rated charging power Pj of the energy storage 50. 充 The purpose of the invention is to reduce the damage to the energy storage 50 and to increase the service life of the energy storage 50.

[0109] In order to ensure the balance of power absorption for each phase, the energy storage 50 absorbs power according to its rated charging power Pj. 充 One third of the total power absorption of each phase is charged until the total power absorption of each phase is met.

[0110] Those skilled in the art should know that if there is a phase with an updated single-phase power deviation of zero, its total power absorption will also be zero, then the energy storage 50 does not need to absorb power from this phase, but only needs to absorb power from other phases whose total discharge power is not zero according to one third of its own rated charging power until the total power absorption of this phase is met.

[0111] During the process of absorbing electricity, in order to prevent the charge state of the energy storage 50 from being too high, the energy storage 50 will be damaged if it continues to absorb electricity. As an optional implementation method, the charge state of the energy storage 50 will be detected in real time. If the charge state of the energy storage 50 is greater than the second preset charge state, the absorption of electricity will be stopped; if the charge state of the energy storage 50 is greater than or equal to the second preset charge state, the absorption of electricity will continue.

[0112] The second preset state of charge is greater than the first preset state of charge; and the sum of the first preset state of charge and the second preset state of charge is 100%.

[0113] Those skilled in the art will appreciate that the above embodiments are exemplary and are not intended to limit the present application. Where possible, the execution order of one or more of the above steps may be adjusted, or may be selectively combined to obtain one or more other embodiments. Those skilled in the art may select and combine any of the above steps as needed, and all those that do not depart from the essence of the present application fall within the scope of protection of the present application.

[0114] A method for treating three-phase imbalance provided by an embodiment of the present invention comprises the following steps: when a three-phase imbalance occurs, the three-phase imbalance is obtained according to the maximum power deviation between phases and the total power of the three phases; when the three-phase imbalance is greater than a preset imbalance, the single-phase power deviation of each phase is calculated according to the three-phase average power and the single-phase power of each phase; when the total power of the three phases is greater than a preset area load rate, the single-phase power deviation greater than or equal to zero is updated to zero, and the single-phase power deviation less than zero is updated to its absolute value; the energy storage determines the total discharge power of each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage discharges each phase until the total discharge power of each phase is met; when the total power of the three phases is less than the preset area load rate, the single-phase power deviation less than or equal to zero is updated to zero, and the single-phase power deviation greater than zero is updated to itself; the energy storage determines the total power absorption of each phase according to its updated single-phase power deviation, proportional gain and integral gain; the energy storage absorbs power from each phase until the total power absorption of each phase is met. On the one hand, since the single-phase power deviation is updated according to different situations while considering the load rate of the substation, the total discharge power or total power absorption of the energy storage for each phase is determined by the updated single-phase power deviation, proportional gain and integral gain, which can make the energy storage more accurately regulate each phase and reduce the occurrence of substation overload or substation backfeed. On the second hand, without increasing new equipment investment or system reconstruction, the energy storage is empowered to have the function of substation three-phase power imbalance management, and the equipment application is expanded to help the construction of new power systems. On the third hand, the management method is used to use the substation load as the basis for charging and discharging judgment in the energy storage management process. In the process of managing three-phase power imbalance, the occurrence of substation overload and substation reverse overload can be reduced, and the effect of energy storage power quality management is maximized. On the fourth hand, since the number of substation overload and substation reverse overload phenomena is reduced, the occurrence of line damage due to heat can be reduced, the service life of the line is increased, and the time when the substation does not need to be renovated can be extended, thereby improving economic benefits.

[0115] An embodiment of a micro energy regulator:

[0116] An embodiment of the present invention provides a micro energy regulator, comprising a processor, wherein the processor executes a computer program to implement the steps of the aforementioned three-phase imbalance control method.

[0117] For a detailed introduction to the micro energy regulator, please refer to the related description in the aforementioned embodiment of "a method for controlling three-phase imbalance", which will not be repeated here.

[0118] A micro energy regulator provided by an embodiment of the present invention can achieve the same beneficial effects as the aforementioned "a method for controlling three-phase imbalance", which will not be described in detail here.

Claims

1. A method for treating three-phase imbalance, characterized in that: The steps include: When three-phase imbalance occurs, the three-phase imbalance degree is obtained according to the maximum power deviation between phases and the total power of three phases; When the three-phase unbalance is greater than the preset unbalance, the single-phase power deviation of each phase is calculated according to the three-phase average power and the single-phase power of each phase; When the three-phase total power is greater than the preset area load rate, the single-phase power deviation greater than or equal to zero is updated to zero, and the single-phase power deviation less than zero is updated to its absolute value; the energy storage determines the total discharge power for each phase according to its updated single-phase power deviation, its previous accumulated deviation, proportional gain and integral gain; the energy storage discharges each phase until the total discharge power of each phase is met; When the total three-phase power is less than the preset substation load rate, the single-phase power deviation that is less than or equal to zero is updated to zero, and the single-phase power deviation that is greater than zero is updated to itself; the energy storage determines the total power absorption for each phase based on its updated single-phase power deviation, its previous accumulated deviations, proportional gain and integral gain; the energy storage absorbs power from each phase until the total power absorption of each phase is met.

2. The three-phase imbalance control method according to claim 1 is characterized in that: When the total power of the three phases is greater than the preset area load rate, the energy storage discharges each phase at one third of its rated discharge power; When the total power of the three phases is less than the preset area load rate, the energy storage absorbs electricity from each phase according to one third of its rated charging power.

3. The three-phase imbalance control method according to claim 1 is characterized in that: During the process of discharging each phase of the energy storage, if the state of charge of the energy storage is less than a first preset state of charge, the discharging is stopped; During the process of the energy storage absorbing electricity from each phase, if the state of charge of the energy storage is greater than a second preset state of charge, charging is stopped; Among them, the second preset state of charge is greater than the first preset state of charge; the sum of the first preset state of charge and the second preset state of charge is 100%.

4. The method for treating three-phase imbalance according to any one of claims 1 to 3, characterized in that: The three-phase unbalance degree is a quotient obtained by dividing the maximum power deviation between phases by the three-phase total power.

5. The three-phase imbalance control method according to claim 4 is characterized in that: The maximum power deviation between phases and the corresponding three-phase total power are collected multiple times, and the quotient of the maximum power deviation between phases and the corresponding three-phase total power is calculated, and the average is used as the three-phase imbalance.

6. The three-phase imbalance control method according to claim 5, characterized in that: When it is necessary to collect the three-phase total power for multiple times, the three-phase total power compared with the preset station area load rate is the average three-phase total power obtained after collecting the three-phase total power for multiple times.

7. The method for treating three-phase imbalance according to any one of claims 1 to 3, characterized in that: The single-phase power deviation=the three-phase average power-the single-phase power.

8. The three-phase imbalance control method according to claim 7, characterized in that: The single-phase power deviation is also calculated according to the control ratio parameter; The single-phase power deviation=(the three-phase average power-the single-phase power)*the control ratio parameter.

9. The method for treating three-phase imbalance according to claim 1, characterized in that: The energy storage adopts PI control to discharge or absorb electricity from each phase.

10. A micro energy regulator, comprising a processor, characterized in that: The processor executes a computer program to implement the steps of the three-phase unbalance control method as described in any one of claims 1-9.

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