A low voltage control method and system

Abstract

The present invention discloses a low voltage management method and system, which is applied to the field of smart grid control technology. The method includes: obtaining the load characteristics and user characteristics of each branch in the substation to be managed; selecting branches that can be used for energy storage equipment to manage low voltage as candidate branches according to the load characteristics and user characteristics; obtaining the electrical characteristic data of users of the candidate branches; the electrical characteristic data includes user voltage data, user power data and distribution transformer power data; configuring energy storage equipment for the candidate branches to manage low voltage according to the electrical characteristic data; obtaining electrical characteristic data at a preset period, and updating the parameters of the energy storage equipment and the low voltage management plan according to the newly obtained electrical characteristic data. The present invention can formulate an energy storage and energy replenishment plan suitable for the rural power grid line without examining the resistance of the rural power grid line in detail, and can periodically modify the plan at the same time. It has excellent applicability and is particularly suitable for rural power grids in mountainous areas with long line lengths.

Description

Technical Field

[0001] The present invention relates to smart grid control technology, and in particular to a low voltage management method and system. Background Art

[0002] In rural areas, villages are scattered, the number of households is small, and they are far away from the backbone power grid. There are generally problems such as large power supply radius, long lines, and poor grid load capacity. During agricultural production such as tea baking / irrigation, the return of young people during the Spring Festival / winter and summer vacations, and the start-up of high-power electrical appliances at the end, the load rises sharply, causing the line current to increase, the conductor voltage drop to be large, and the intermittent low voltage problem to become prominent.

[0003] The prior art provides a variety of solutions for dealing with low voltage in rural power grid areas. For example, the Chinese patent with application number 202211624455.1 discloses a user low voltage management method based on energy storage regulation, including: S1, determining the installation location of the multi-energy complementary low voltage management device based on the low voltage monitoring of the distribution user; S2, determining the installation capacity and power of the multi-energy complementary low voltage management device according to the deviation between the average value of the lowest voltage of the monitored low voltage user and the standard voltage; S3, installing the multi-energy complementary low voltage management device at the installation location according to the installation capacity; S4, performing user low voltage management through the multi-energy complementary low voltage management device. The load side voltage can be adjusted in real time by working together with the grid-side inverter and the load-side inverter. It provides a technical solution for low voltage regulation through energy storage equipment, but the line resistance voltage division in rural power grid areas is serious, and how to quickly and accurately configure the corresponding energy storage equipment and the corresponding energy replenishment solution has become a problem. Summary of the invention

[0004] In order to at least overcome the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a low voltage management method and system.

[0005] In a first aspect, the present application provides a low voltage management method, comprising:

[0006] Obtain the load characteristics and user characteristics of each branch in the area to be managed; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user;

[0007] Selecting branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics;

[0008] Acquire electrical characteristic data of users of the candidate branch; the electrical characteristic data includes user voltage data, user power data and distribution transformer power data;

[0009] According to the electrical characteristic data, an energy storage device is configured for the candidate branch to perform low voltage management;

[0010] The electrical characteristic data is acquired at a preset period, and the parameters and low voltage management scheme of the energy storage device are updated according to the newly acquired electrical characteristic data.

[0011] When implementing the embodiments of the present application, it is necessary to first screen out branches that can be managed with low voltage by energy storage devices. The reason is that low voltage management by energy storage devices is the last link in low voltage management, that is, low voltage management by energy storage devices is required only when management cannot be completed by other means; branches that need to be managed with low voltage by energy storage devices can be effectively screened out as alternative branches through load characteristics and user characteristics.

[0012] In an embodiment of the present application, when configuring an energy storage device for an alternative branch, it is necessary to calculate the relevant parameters of the energy storage device through electrical characteristics, and the calculated content mainly includes the energy storage upper limit of the energy storage device, the configured photovoltaic energy replenishment, and the corresponding charging and discharging rules. According to the calculated content, the low voltage management of the alternative branch can be effectively achieved. At the same time, in an embodiment of the present application, the energy storage device and the charging and discharging scheme can also be adjusted according to a preset cycle to achieve long-term low voltage management of the alternative branch. Generally, the preset cycle adopts one month or one quarter. Through the above-mentioned technical means, the present application can formulate an energy storage and energy replenishment scheme suitable for the rural power grid line without detailed investigation of the resistance of the rural power grid line, and the scheme can be periodically revised at the same time, which has excellent applicability, especially suitable for mountainous rural power grids with longer line lengths.

[0013] In a possible implementation, selecting a branch that can be used for low voltage management of an energy storage device as a candidate branch according to the load characteristics and the user characteristics includes:

[0014] The branch whose load characteristics and user characteristics meet the preset conditions is selected as a candidate branch;

[0015] The preset conditions include:

[0016] The heavy overload duration accounts for less than 60% of the total duration; the power factor is normal; the three-phase imbalance is normal; and the low voltage duration accounts for less than 30% of the total duration.

[0017] In a possible implementation, configuring an energy storage device for the candidate branch to perform low voltage management according to the electrical characteristic data includes:

[0018] Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters;

[0019] The energy storage device is charged and discharged according to the electrical characteristic data of the current user of the alternative branch to achieve dynamic low voltage management of the alternative branch.

[0020] In a possible implementation, calculating the parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters includes:

[0021] Divide a day into 96 time nodes at 15-minute intervals;

[0022] Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node;

[0023] Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph;

[0024] In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold;

[0025] Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data;

[0026] Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data;

[0027] Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period;

[0028] Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period;

[0029] Calculate the difference between the charging distribution and transformation electric energy and the charging user electric energy data as the chargeable electric energy, and calculate the difference between the discharging user electric energy data and the discharging distribution and transformation electric energy as the required discharging electric energy;

[0030] Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device;

[0031] An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

[0032] In a possible implementation, controlling the charging and discharging of the energy storage device according to the electrical characteristic data of the current user of the candidate branch to achieve dynamic low voltage management of the candidate branch includes:

[0033] When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power;

[0034] When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

[0035] In a possible implementation, updating the parameters and low voltage management scheme of the energy storage device according to the newly acquired electrical characteristic data includes:

[0036] Generate a new characteristic power diagram as a management characteristic power diagram according to the newly acquired electrical characteristic data, and draw a new discharge voltage curve as a management discharge curve and a new charge voltage curve as a management charge curve on the management characteristic power diagram;

[0037] According to the control characteristic power diagram, the control discharge curve and the control charging curve, new chargeable electric energy is calculated as control charging electric energy, and new required discharge electric energy is calculated as control discharge electric energy;

[0038] When the managed discharged electric energy is greater than a preset value, the managed discharged electric energy is used as the newly added stored energy to expand the capacity of the energy storage device;

[0039] When the difference between the managed discharge electric energy and the managed charge electric energy is greater than a preset value, the capacity of the photovoltaic power generation equipment is expanded according to the difference;

[0040] When the energy storage device or the photovoltaic power generation device is expanded, a new charging and discharging plan is generated.

[0041] In a second aspect, the present application also provides a low voltage management system, including:

[0042] The first acquisition unit is configured to acquire the load characteristics and user characteristics of each branch in the to-be-managed substation; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user;

[0043] A screening unit is configured to screen out branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics;

[0044] A second acquisition unit is configured to acquire electrical characteristic data of users of the candidate branch; the electrical characteristic data includes user voltage data, user power data and distribution transformer power data;

[0045] The management unit is configured to configure an energy storage device for the candidate branch to perform low voltage management according to the electrical characteristic data.

[0046] In a possible implementation, the governance unit is further configured to:

[0047] Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters;

[0048] The energy storage device is charged and discharged according to the electrical characteristic data of the current user of the alternative branch to achieve dynamic low voltage management of the alternative branch.

[0049] In a possible implementation, the governance unit is further configured to:

[0050] Divide a day into 96 time nodes at 15-minute intervals;

[0051] Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node;

[0052] Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph;

[0053] In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold;

[0054] Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data;

[0055] Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data;

[0056] Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period;

[0057] Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period;

[0058] Calculate the difference between the charging distribution and transformation electric energy and the charging user electric energy data as the chargeable electric energy, and calculate the difference between the discharging user electric energy data and the discharging distribution and transformation electric energy as the required discharging electric energy;

[0059] Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device;

[0060] An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

[0061] In a possible implementation, the governance unit is further configured to:

[0062] When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power;

[0063] When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

[0064] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0065] The present invention can formulate energy storage and energy replenishment schemes suitable for rural power grid lines without detailed examination of the resistance of the rural power grid lines, and can periodically modify the schemes. It has excellent applicability and is particularly suitable for rural power grids in mountainous areas with long lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0067] Figure 1 This is a schematic diagram of the steps of the method of the embodiment of the present application;

[0068] Figure 2This is a schematic diagram of the characteristic power diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0069] To make the purpose, technical scheme and advantages of the embodiment of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the embodiment of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0070] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0071] Please refer to Figure 1 , is a flow chart of a low voltage management method provided in an embodiment of the present invention. Furthermore, the low voltage management method may specifically include the contents described in the following steps S1 to S5.

[0072] S1: Obtain the load characteristics and user characteristics of each branch in the area to be managed; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user;

[0073] S2: selecting branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics;

[0074] S3: Acquire electrical characteristic data of the user of the candidate branch; the electrical characteristic data includes user voltage data, user power data and distribution transformer power data;

[0075] S4: configuring energy storage equipment for the candidate branch according to the electrical characteristic data to perform low voltage management;

[0076] S5: Acquire the electrical characteristic data at a preset period, and update the parameters and low voltage management scheme of the energy storage device according to the newly acquired electrical characteristic data.

[0077] When implementing the embodiments of the present application, it is necessary to first screen out branches that can be managed with low voltage by energy storage devices. The reason is that low voltage management by energy storage devices is the last link in low voltage management, that is, low voltage management by energy storage devices is required only when management cannot be completed by other means; branches that need to be managed with low voltage by energy storage devices can be effectively screened out as alternative branches through load characteristics and user characteristics.

[0078] In an embodiment of the present application, when configuring an energy storage device for an alternative branch, it is necessary to calculate the relevant parameters of the energy storage device through electrical characteristics, and the calculated content mainly includes the energy storage upper limit of the energy storage device, the configured photovoltaic energy replenishment, and the corresponding charging and discharging rules. According to the calculated content, the low voltage management of the alternative branch can be effectively achieved. At the same time, in an embodiment of the present application, the energy storage device and the charging and discharging scheme can also be adjusted according to a preset cycle to achieve long-term low voltage management of the alternative branch. Generally, the preset cycle adopts one month or one quarter. Through the above-mentioned technical means, the present application can formulate an energy storage and energy replenishment scheme suitable for the rural power grid line without detailed investigation of the resistance of the rural power grid line, and the scheme can be periodically revised at the same time, which has excellent applicability, especially suitable for mountainous rural power grids with longer line lengths.

[0079] In a possible implementation, selecting a branch that can be used for low voltage management of an energy storage device as a candidate branch according to the load characteristics and the user characteristics includes:

[0080] The branch whose load characteristics and user characteristics meet the preset conditions is selected as a candidate branch;

[0081] The preset conditions include:

[0082] The heavy overload duration accounts for less than 60% of the total duration; the power factor is normal; the three-phase imbalance is normal; and the low voltage duration accounts for less than 30% of the total duration.

[0083] When the embodiments of the present application are implemented, different management solutions can be provided for branches in different states when screening alternative branches. For example, for branches where the heavy overload duration accounts for 60% or more of the total duration, it is necessary to consider increasing the capacity of the substation or adding a new distribution transformer; for branches with abnormal power factor, it is necessary to consider increasing reactive power compensation; for branches with three-phase imbalance, it is necessary to consider adding phase-changing switches; for branches where the low voltage duration accounts for 30% or more of the total duration, it is necessary to consider adding a voltage regulator; and for branches that meet the preset conditions, low voltage management can be carried out by adding new energy storage equipment.

[0084] In a possible implementation, configuring an energy storage device for the candidate branch to perform low voltage management according to the electrical characteristic data includes:

[0085] Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters;

[0086] The energy storage device is charged and discharged according to the electrical characteristic data of the current user of the alternative branch to achieve dynamic low voltage management of the alternative branch.

[0087] When the embodiment of the present application is implemented, the electrical characteristic data can be used to calculate the relevant parameters of the energy storage device and generate a charging and discharging plan for the energy storage device, which can facilitate timely adjustment of the energy storage device and the charging and discharging plan in the process of continuously acquiring electrical characteristics.

[0088] In a possible implementation, calculating the parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters includes:

[0089] Divide a day into 96 time nodes at 15-minute intervals;

[0090] Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node;

[0091] Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph;

[0092] In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold;

[0093] Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data;

[0094] Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data;

[0095] Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period;

[0096] Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period;

[0097] Calculate the difference between the charging distribution and transformation electric energy and the charging user electric energy data as the chargeable electric energy, and calculate the difference between the discharging user electric energy data and the discharging distribution and transformation electric energy as the required discharging electric energy;

[0098] Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device;

[0099] An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

[0100] When the embodiment of the present application is implemented, the acquisition of electrical characteristic data adopts the common 96-point data in the industry, that is, data sampling is performed every 15 minutes, and the sampling content needs to include user power data and user voltage data, and the distribution transformer power data is generally fixed for a branch, and can be obtained from the distribution transformer. In the embodiment of the present application, the concept of characteristic power is proposed, and each time node will correspond to a characteristic power. The characteristic power is used to characterize the maximum value of the total power of all users of this branch at a certain time node in multiple consecutive days. At the same time, it is also necessary to obtain the minimum voltage of all users at this time node as the characteristic voltage.

[0101] The characteristic power graph can be constructed by using the characteristic power and the corresponding time nodes. Figure 2 , shows the construction of a characteristic power diagram. It is obvious that the power consumption during the daytime corresponding to the middle part is much greater than the nighttime periods at both ends. Figure 2 The horizontal axis of the curve in the figure is the time node, from 1 to 96; the vertical axis is the characteristic power. In the characteristic power diagram, each point actually corresponds to three data, namely the characteristic power, characteristic voltage and time node; in order to more accurately analyze the low voltage situation that needs to be managed, the inventor used the discharge voltage curve and the charging voltage curve for related parameter analysis; the discharge voltage curve uses the discharge voltage threshold, which is generally around 205V; the charging voltage curve uses the charging voltage threshold, which is generally around 215V; the discharge voltage curve and the charging voltage curve are drawn as shown in Figure 2As shown. The drawing process can be obtained by interpolating and offsetting the voltage values ​​at different points. It can be found from the figure that the charging voltage curve and the discharging voltage curve are basically close to a straight line. The reason is that for a branch, the maximum power value and the minimum voltage value show an approximately linear correlation when the line resistance is stable. Therefore, the voltage value in the entire characteristic power diagram can be linearly interpolated to directly obtain the corresponding discharge voltage curve and charging voltage curve.

[0102] In an embodiment of the present application, the characteristic power curve above the discharge voltage curve represents the part that needs to be compensated for electric energy under low voltage conditions, while the part below the charging voltage curve represents the part that can be charged under stable voltage. Based on this principle, the discharge user electric energy data and the discharge period corresponding to the discharge user electric energy data can be calculated, and the charging user electric energy data and the charging period corresponding to the charging user electric energy data can be calculated. At this time, according to the distribution transformer power data, the electric energy that can be provided by the distribution transformer under normal circumstances can be calculated, and the rechargeable electric energy and the electric energy to be discharged can be calculated. The electric energy to be discharged here represents the energy storage upper limit of the energy storage device that needs to be increased, and the difference between the rechargeable electric energy and the electric energy to be discharged represents the charging electric energy gap, and the gap here needs to be supplemented by photovoltaics. Based on the above calculation process, the parameters of the energy storage equipment and photovoltaic equipment that need to be added can be determined more accurately, and then the equipment can be deployed.

[0103] In a possible implementation, controlling the charging and discharging of the energy storage device according to the electrical characteristic data of the current user of the candidate branch to achieve dynamic low voltage management of the candidate branch includes:

[0104] When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power;

[0105] When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

[0106] When the embodiments of the present application are implemented, after the discharge period and the discharge period are clarified, the charging and discharging of the energy storage device can be controlled in a dynamic manner, and the process is to make up for the power gap by discharging, and charge the energy storage device with the power surplus; the dynamic control process can be achieved through the existing energy storage control scheme, and the embodiments of the present application do not make much limitation.

[0107] In a possible implementation, updating the parameters and low voltage management scheme of the energy storage device according to the newly acquired electrical characteristic data includes:

[0108] Generate a new characteristic power diagram as a management characteristic power diagram according to the newly acquired electrical characteristic data, and draw a new discharge voltage curve as a management discharge curve and a new charge voltage curve as a management charge curve on the management characteristic power diagram;

[0109] According to the control characteristic power diagram, the control discharge curve and the control charging curve, new chargeable electric energy is calculated as control charging electric energy, and new required discharge electric energy is calculated as control discharge electric energy;

[0110] When the managed discharged electric energy is greater than a preset value, the managed discharged electric energy is used as the newly added stored energy to expand the capacity of the energy storage device;

[0111] When the difference between the managed discharge electric energy and the managed charge electric energy is greater than a preset value, the capacity of the photovoltaic power generation equipment is expanded according to the difference;

[0112] When the energy storage device or the photovoltaic power generation device is expanded, a new charging and discharging plan is generated.

[0113] When the embodiment of the present application is implemented, since the data source only depends on the characteristic power diagram in the process of generating parameters and schemes of the energy storage device, the relevant parameters of the energy storage device are updated based on the same conception to better adapt to the rural power grid environment; in the process of updating, the calculation process of managing charging power and managing discharging power is the same as the above embodiment, and this embodiment does not make much limitation; if the current branch has completed the low voltage management well, then the position of the management discharge curve on the management characteristic power diagram will be above the characteristic power curve, so that the management discharge power is 0, in this case, the parameters of the energy storage device do not need to be adjusted; and when the management discharge power is greater than the preset value, it means that the energy storage capacity needs to be further increased, and the expansion capacity of the photovoltaic device can also be calculated based on the above data. In actual practice, the inventor found that it is generally difficult to fully meet the low voltage management requirements with one adjustment, so this cyclic iteration method is used to adjust the parameters, which can effectively find the final optimal low voltage management solution, and at the same time, it can effectively deal with the situation of continuous increase in line resistance, without having to care about how much the line resistance has increased, which greatly reduces the cost of low voltage management in rural areas. In the embodiment of the present application, a new charging and discharging scheme can also be generated according to the scheme in the above embodiment.

[0114] Based on the same inventive concept, the present application also provides a low voltage management system, including:

[0115] The first acquisition unit is configured to acquire the load characteristics and user characteristics of each branch in the to-be-managed substation; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user;

[0116] A screening unit is configured to screen out branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics;

[0117] A second acquisition unit is configured to acquire electrical characteristic data of users of the candidate branch; the electrical characteristic data includes user voltage data, user power data and distribution transformer power data;

[0118] The management unit is configured to configure an energy storage device for the candidate branch to perform low voltage management according to the electrical characteristic data.

[0119] In a possible implementation, the governance unit is further configured to:

[0120] Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters;

[0121] The energy storage device is charged and discharged according to the electrical characteristic data of the current user of the alternative branch to achieve dynamic low voltage management of the alternative branch.

[0122] In a possible implementation, the governance unit is further configured to:

[0123] Divide a day into 96 time nodes at intervals of 15 minutes;

[0124] Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node;

[0125] Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph;

[0126] In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold;

[0127] Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data;

[0128] Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data;

[0129] Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period;

[0130] Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period;

[0131] Calculate the difference between the charging distribution and transformation electric energy and the charging user electric energy data as the chargeable electric energy, and calculate the difference between the discharging user electric energy data and the discharging distribution and transformation electric energy as the required discharging electric energy;

[0132] Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device;

[0133] An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

[0134] In a possible implementation, the governance unit is further configured to:

[0135] When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power;

[0136] When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

[0137] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0138] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0139] The units described as separate components may or may not be physically separated. As units, it is obvious that a person of ordinary skill in the art can realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0140] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0141] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a grid device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0142] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low voltage control method, characterized in that: include: Obtain the load characteristics and user characteristics of each branch in the area to be managed; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user; Selecting branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics; Acquiring electrical characteristic data of users of the candidate branch; The electrical characteristic data includes user voltage data, user power data and distribution transformer power data; According to the electrical characteristic data, an energy storage device is configured for the candidate branch to perform low voltage management; Acquire the electrical characteristic data at a preset period, and update the parameters and low voltage management scheme of the energy storage device according to the newly acquired electrical characteristic data; Configuring energy storage equipment for the candidate branch according to the electrical characteristic data to perform low voltage management includes: Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters; According to the electrical characteristic data of the current user of the candidate branch, the energy storage device is charged and discharged to realize dynamic low voltage management of the candidate branch; Calculating the parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters includes: Divide a day into 96 time nodes at 15-minute intervals; Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node; Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph; In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold; Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data; Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data; Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period; Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period; Calculate the difference between the charging distribution and transformation electric energy and the charging user electric energy data as the chargeable electric energy, and calculate the difference between the discharging user electric energy data and the discharging distribution and transformation electric energy as the required discharging electric energy; Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device; An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

2. A low voltage control method according to claim 1, characterized in that: According to the load characteristics and the user characteristics, branches that can be used for low voltage management of energy storage equipment are selected as candidate branches, including: The branch whose load characteristics and user characteristics meet the preset conditions is selected as a candidate branch; The preset conditions include: The heavy overload duration accounts for less than 60% of the total duration; the power factor is normal; the three-phase imbalance is normal; and the low voltage duration accounts for less than 30% of the total duration.

3. A low voltage control method according to claim 1, characterized in that: The charging and discharging control of the energy storage device according to the electrical characteristic data of the current user of the candidate branch to achieve dynamic low voltage management of the candidate branch includes: When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power; When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

4. A low voltage control method according to claim 1, characterized in that: Updating the parameters and low voltage management scheme of the energy storage device according to the newly acquired electrical characteristic data includes: Generate a new characteristic power diagram as a management characteristic power diagram according to the newly acquired electrical characteristic data, and draw a new discharge voltage curve as a management discharge curve and a new charge voltage curve as a management charge curve on the management characteristic power diagram; According to the control characteristic power diagram, the control discharge curve and the control charging curve, new chargeable electric energy is calculated as control charging electric energy, and new required discharge electric energy is calculated as control discharge electric energy; When the managed discharged electric energy is greater than a preset value, the managed discharged electric energy is used as the newly added stored energy to expand the capacity of the energy storage device; When the difference between the managed discharge electric energy and the managed charge electric energy is greater than a preset value, the photovoltaic power generation equipment is expanded according to the difference; When the energy storage device or the photovoltaic power generation device is expanded, a new charging and discharging plan is generated.

5. A low voltage management system, characterized in that: include: The first acquisition unit is configured to acquire the load characteristics and user characteristics of each branch in the to-be-managed substation; the load characteristics include the duration of heavy overload, power factor and three-phase imbalance; the user characteristics include the duration of low voltage of the user; A screening unit is configured to screen out branches that can be used for low voltage management of energy storage equipment as candidate branches according to the load characteristics and the user characteristics; A second acquisition unit is configured to acquire electrical characteristic data of a user of the candidate branch; The electrical characteristic data includes user voltage data, user power data and distribution transformer power data; A management unit, configured to configure an energy storage device for the candidate branch to perform low voltage management according to the electrical characteristic data; The governance unit is further configured to: Calculating parameters of the energy storage device configured for the candidate branch according to the electrical characteristic data, and configuring the energy storage device for the candidate branch according to the parameters; According to the electrical characteristic data of the current user of the candidate branch, the energy storage device is charged and discharged to realize dynamic low voltage management of the candidate branch; The governance unit is further configured to: Divide a day into 96 time nodes at 15-minute intervals; Obtain the maximum value of the total power of all users of the candidate branch at each time node for multiple consecutive days as the characteristic power corresponding to the time node, and obtain the characteristic voltage corresponding to the characteristic power; the characteristic voltage is the minimum voltage value of the user corresponding to the time node; Constructing a characteristic power curve along the time node of the characteristic power to form a characteristic power graph; In the characteristic power diagram, a discharge voltage curve is drawn according to the distribution of the characteristic voltage using a preset discharge voltage threshold, and a charge voltage curve is drawn according to the distribution of the characteristic voltage using a preset charge voltage threshold; Calculating the integral of the characteristic power curve above the discharge voltage curve along time as the discharge user power data, and obtaining the discharge time period corresponding to the discharge user power data; Calculating the integral of the characteristic power curve below the charging voltage curve along time as charging user power data, and obtaining a charging time period corresponding to the charging user power data; Calculate the distribution transformer power energy in the discharge period as the discharge distribution transformer power energy according to the distribution transformer power data and the discharge period; Calculate the distribution transformer power energy in the charging period as the charging distribution transformer power energy according to the distribution transformer power data and the charging period; Calculate the difference between the charging distribution and transformation power and the charging user power data as the chargeable power, and calculate the difference between the discharging user power data and the discharging distribution and transformation power as the required discharging power; Calculate the difference between the required discharge electric energy and the rechargeable electric energy as the electric energy required by the energy storage device through photovoltaic energy replenishment to form photovoltaic energy replenishment data, and use the required discharge electric energy as the energy storage upper limit of the energy storage device; An energy storage device is configured for the alternative branch according to the energy storage upper limit, and a corresponding photovoltaic power generation device is configured for the energy storage device according to the photovoltaic energy replenishment data.

6. A low voltage management system according to claim 5, characterized in that: The governance unit is further configured to: When in the discharging period, calculating the difference between the user power data and the distribution transformer power data in the electrical characteristic data of the current user as power gap data, and controlling the energy storage device to discharge with the power gap data as the discharging power; When in the charging period, the difference between the distribution transformer power data and the user power data in the electrical characteristic data of the current user is calculated as power margin data, and the energy storage device is controlled to charge with the power margin data as the charging electric power.

Images