Power grid low-voltage treatment control method

Abstract

The invention provides a power grid low-voltage governance control method, which comprises the steps of S1, acquiring parameter information related to transformer area governance, including data of a power grid side, a resident side and a direct current side; s2, when the voltage of the power grid side reaches a preset range, battery charging maintenance is carried out; and S3, when the voltage of the power grid side is lower than the preset voltage, reactive compensation is carried out, the photovoltaic and battery voltage SOC states are judged at the same time, and the voltage of the power grid side is raised by adopting a negative feedback proportional-integral mode to carry out inversion supplementary load. According to the method, rapid low-cost adjustment can be realized when the voltage of the power grid is too low.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid voltage control, and in particular to a power grid low voltage management control method. Background Art

[0002] At present, the low voltage problem and unstable power supply in some areas are mainly caused by the following reasons: 1. Aging of power supply facilities and insufficient distribution of distribution transformers: In some remote mountainous areas and rural areas, due to the dispersion of users, insufficient distribution of transformers, small capacity and long commissioning time, the service life of electrical equipment is long, the distribution line diameter is small, the distribution transformer capacity is insufficient, and there are many low-voltage faults in the line, resulting in frequent low voltage phenomena. 2. Increased electricity consumption and mismatch between supply and demand: With the rapid economic development, the electricity consumption of rural users has increased rapidly, and the overload operation problems of distribution transformers and distribution lines are serious. The mismatch between electricity supply and demand, coupled with the relatively concentrated electricity consumption period in rural areas, have led to increasingly serious low voltage problems. 3. Line loss management problems in the substation area: Problems in the line loss management work in the substation area, such as damage to the metering equipment or errors in the filing data, inconsistent transformer ratio data in the assessment table, etc., will lead to errors in the line loss rate, affecting the normal operation and management of the substation area.

[0003] In order to solve the above problems, traditional technologies generally use the method of adding transformers and transforming lines. Although this kind of power transformation technology is effective in improving power supply, these methods have some obvious limitations. First, the cost of these transformations is high and the implementation period is long, which makes it difficult to recover costs. Secondly, due to the complexity of the transformation process, there may be problems of insufficient supervision and lack of intelligent management, resulting in low overall efficiency. The solution of adding transformers may also cause low voltage during peak power consumption in some rural areas due to unreasonable design, and it is impossible to effectively compensate, and it is impossible to respond quickly after monitoring the phenomenon because the implementation cost is high. In addition, these traditional methods may also affect residents' electricity experience during implementation, because construction and transformation activities may temporarily interrupt power supply or reduce power supply quality.

[0004] Therefore, in order to solve the power supply problem in local areas more efficiently and economically, it is necessary to explore new technologies and management strategies to reduce costs, shorten construction periods, and improve the stability and reliability of power supply. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for controlling low voltage in a power grid, so as to achieve rapid and low-cost regulation of low voltage in the power grid.

[0006] The present invention is implemented as follows: a low voltage control method for a power grid, the method comprising:

[0007] Step S1, obtaining parameter information related to the area management, including data on the grid side, the residential side and the DC side;

[0008] Step S2: When the grid voltage reaches a preset range, battery charging maintenance is performed;

[0009] Step S3: When the grid-side voltage is lower than the preset voltage, reactive power compensation is performed, and the SOC status of the photovoltaic and battery voltages is determined at the same time, and a negative feedback proportional integral method is used to invert and supplement the load to raise the grid-side voltage.

[0010] Furthermore, the DC side includes a photovoltaic charger and an energy storage battery, and the photovoltaic charger and the energy storage battery are connected to the grid side and the resident side through an inverter, and the inverter is regulated by an external controller.

[0011] Furthermore, the parameter information specifically includes the real-time voltage, current, output active power, reactive power on the grid side, load consumption power on the resident side, and photovoltaic power on the DC side.

[0012] Furthermore, the step S2 is specifically as follows: determine whether the SOC value of the energy storage battery on the battery side is lower than a set value. If so, photovoltaic charging is prioritized. If photovoltaic charging is sufficient, the grid side does not take any action, and the energy storage battery equipment performs photovoltaic energy replenishment. If photovoltaic charging is insufficient, when the grid side voltage reaches a preset range, the grid side is scheduled to provide part of the energy for energy storage charging according to a preset percentage.

[0013] Furthermore, the reactive power compensation in step S3 is automatic compensation performed all the time. The automatic compensation is performed all the time.

[0014] Furthermore, the reactive power compensation in step S3 is compensated by a proportional-integral algorithm through the inverter, and the specific calculation formula is: reactive power compensation value = Kp1×(currently output reactive power - required output reactive power)+Ki1×(currently output reactive power - required output reactive power), wherein the proportional coefficient Kp1 and the integral coefficient Ki1 are obtained through preliminary experimental tests.

[0015] Furthermore, the specific implementation of "using negative feedback proportional integral method to invert and supplement load to raise the voltage on the grid side" in step S3 is as follows:

[0016] Calculate the DC side current that needs to be output each time, and obtain the photovoltaic power for this energy replenishment according to the calculated current value. If the photovoltaic power is insufficient, start the energy storage battery for this energy replenishment until the grid side voltage reaches the preset range and stops this round of compensation; the calculation method of the DC side current that needs to be output is as follows;

[0017] The DC side current that needs to be output this time = current voltage error value × Kp + Ki × the sum of each voltage error value in this round + the current output last time;

[0018] Current voltage error value = current voltage on the grid side - stable voltage setting value;

[0019] The proportional coefficient Kp and the integral coefficient Ki are obtained through preliminary experimental tests, and the default value of the last output current in the first calculation of this round is 0.

[0020] Furthermore, the method also includes step S4, systematically obtaining the underlying equipment information through the background management platform, uploading all valid data to the background storage, and displaying it to relevant personnel for review and analysis, supporting ratio adjustment, and increasing the ratio of the inverter and the energy storage battery according to the analysis results.

[0021] The present invention has the following advantages: by acquiring relevant parameters in real time and calculating the specific values ​​that need to be compensated, reactive power compensation and active power compensation are performed simultaneously, so as to quickly adjust the voltage on the resident side. It can be quickly put into use in areas with serious low voltage in the substation area, thus reducing the cycle and the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0023] Figure 1 The present invention is a flowchart of an execution of a low voltage management control method for a power grid.

[0024] Figure 2 The figure is a schematic diagram of the system structure adopted by a power grid low voltage management control method of the present invention in a specific embodiment.

[0025] Figure 3 The present invention is a flowchart of the execution of reactive power compensation in a power grid low voltage management control method in a specific embodiment of the present invention.

[0026] Figure 4 It is an execution flow chart of active power compensation in a power grid low voltage management control method of the present invention in a specific embodiment. DETAILED DESCRIPTION

[0027] The embodiment of the present application provides a low-voltage power grid management and control method for solving the existing problem of low power grid voltage in some areas, thereby achieving rapid voltage adjustment and reducing construction costs.

[0028] The overall idea of ​​the technical solution in the embodiments of the present application is as follows: by controlling the inverter to perform reactive compensation and active compensation in parallel when low voltage occurs on the grid side, the voltage on the resident side can be increased as quickly as possible, the residents' electricity consumption can be restored, and the management efficiency and residents' experience can be improved.

[0029] In order to better understand the above technical solution, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0030] See also Figures 1 to 4 As shown, the present invention provides a method for controlling low voltage in a power grid, the method comprising:

[0031] Step S1, obtaining parameter information related to the area management, including data on the grid side, the residential side and the DC side;

[0032] Step S2: When the grid voltage reaches a preset range, battery charging maintenance is performed;

[0033] Step S3: When the grid-side voltage is lower than the preset voltage, reactive power compensation is performed, and the SOC status of the photovoltaic and battery voltages is determined at the same time, and a negative feedback proportional integral method is used to invert and supplement the load to raise the grid-side voltage.

[0034] Preferably, the DC side includes a photovoltaic charger and an energy storage battery, and the photovoltaic charger and the energy storage battery are connected to the grid side and the resident side through an inverter, and the inverter is regulated by an external controller.

[0035] Preferably, the parameter information specifically includes the real-time voltage, current, output active power, reactive power on the grid side, load consumption power on the resident side, and photovoltaic power on the DC side.

[0036] Preferably, in a specific implementation, step S2 is specifically as follows: determine whether the SOC value of the energy storage battery on the battery side is lower than a set value, if so, give priority to calling photovoltaic charging, if the photovoltaic is sufficiently charged, the grid side does not act, and the energy storage battery equipment performs photovoltaic energy replenishment, if the photovoltaic is not enough to charge, when the grid side voltage reaches a preset range, the grid side is scheduled to provide part of the energy for energy storage charging according to a preset percentage.

[0037] Preferably, in a specific implementation, the reactive power compensation in step S3 is automatic compensation performed at all times, and can be automatically compensated by a reactive power regulator, that is, regardless of whether the grid voltage is abnormal, the system is compensating reactive power at all times, reducing the reduction of active power caused by reactive power in the grid, saving electric energy, and improving the quality of the grid. Compared with most of the current mechanisms for compensating reactive power, which perform reactive power compensation and active power compensation logic when the grid voltage is abnormal, this solution can achieve normal compensation when the grid voltage is normal, but the reactive power that still exists in the grid drags down the grid quality, thereby reducing the occurrence of low voltage.

[0038] Preferably, in another specific implementation, the reactive power compensation in step S3 is compensated by a proportional-integral algorithm through the inverter, and the specific calculation formula is: reactive power compensation value = Kp1×(currently output reactive power - required output reactive power)+Ki1×(currently output reactive power - required output reactive power), wherein the proportional coefficient Kp1 and the integral coefficient Ki1 are obtained through preliminary experimental tests.

[0039] Preferably, the specific implementation of "using negative feedback proportional integral method to invert and supplement load to raise the voltage on the grid side" in step S3 is as follows:

[0040] Calculate the DC side current that needs to be output each time, and obtain the photovoltaic power for this energy replenishment according to the calculated current value. If the photovoltaic power is insufficient, start the energy storage battery for this energy replenishment until the grid side voltage reaches the preset range and stops this round of compensation; the calculation method of the DC side current that needs to be output is as follows;

[0041] The DC side current that needs to be output this time (DC side photovoltaic + DC side battery) = current voltage error value × Kp + Ki × the sum of each voltage error value in this round + the current output last time;

[0042] Current voltage error value = current voltage on the grid side - stable voltage setting value;

[0043] The proportional coefficient Kp and the integral coefficient Ki are obtained through preliminary experimental tests, and the default value of the last output current in the first calculation of this round is 0.

[0044] For example, the first grid voltage collected is 180V, and the set stable voltage is 220V. The first calculation is: current I0 = Kp×(220-180)+Ki×(220-180)+the current output last time, and the current output last time defaults to 0; assuming that the second grid voltage is 210V and the stable voltage is 220V, the second calculated current I1 = Kp*(220-210)+Ki*(220-180+220-210)+the current output last time, and the calculation is continued until the grid voltage reaches the range of 218-222V, and this round of compensation is stopped.

[0045] Preferably, the method further includes step S4, systematically obtaining the underlying equipment information through the background management platform, uploading all valid data to the background storage, and displaying it to relevant personnel for viewing and analysis, supporting ratio adjustment, increasing the ratio of inverters and energy storage batteries according to the analysis results, and improving management efficiency and resident experience. By setting an alarm mechanism, an alarm is issued when the automatic adjustment fails. After the alarm, relevant personnel can analyze the low voltage of the city power in the area and adopt solutions such as increasing the battery, photovoltaic or inverter ratio to quickly solve the low voltage problem in the area caused by incorrect ratio. For example, it was initially believed that an 8k inverter + 4 sets of batteries were enough for a few households, but due to a wrong assessment, low voltage or unsatisfactory rated power of the inverter will still occur in actual use. This only requires adding an inverter or a battery to achieve the effect of rapid adjustment, and the entire adjustment cycle is short.

[0046] Preferably, the method further comprises collecting all data in the background to form a price difference table for residents to review, and residents can check how much electricity bill they have saved and the effect of voltage compensation in each time period through the price difference table.

[0047] The present invention can make rapid adjustments when low voltage still occurs due to abnormal artificially calculated ratios. Through real-time monitoring in the background, after the alarm is issued, it will detect the low voltage of the city power in the area and conduct analysis. It can quickly solve the low voltage problem in the area caused by incorrect ratios by adding batteries and photovoltaic ratios.

[0048] The present invention only needs to install inverters, batteries, photovoltaics and other products into a cabinet with a high protection level. When the grid voltage is instantly lowered, the battery discharge (active power compensation) and reactive power regulation are prioritized to raise the mains power. The reactive power can be subsequently adjusted to a relatively small value to reduce the battery discharge, and the photovoltaic replacement battery discharge and the extra energy for battery replenishment are simultaneously attempted. Rapid response and flexible regulation are achieved, and the mains voltage is effectively and quickly adjusted to reach the expected target value, the user-side voltage is prioritized, and then the self-system is adjusted to reduce energy consumption, and charging is performed under possible conditions, reducing frequent deep charging and discharging, so that the system can maintain the low voltage of the mains for a longer period of time.

[0049] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for controlling low voltage in a power grid, characterized in that: The method comprises: Step S1, obtaining parameter information related to the area management, including data on the grid side, the residential side and the DC side; Step S2: When the grid voltage reaches a preset range, battery charging maintenance is performed; Step S3: When the grid-side voltage is lower than the preset voltage, reactive power compensation is performed, and the SOC status of the photovoltaic and battery voltages is determined at the same time, and a negative feedback proportional integral method is used to invert and supplement the load to raise the grid-side voltage.

2. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The DC side includes a photovoltaic charger and an energy storage battery. The photovoltaic charger and the energy storage battery are connected to the grid side and the resident side through an inverter. The inverter is regulated by an external controller.

3. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The parameter information specifically includes the real-time voltage, current, output active power, reactive power on the grid side, load consumption power on the resident side, and photovoltaic power on the DC side.

4. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The step S2 is specifically as follows: determining whether the SOC value of the energy storage battery on the battery side is lower than a set value, if so, giving priority to calling photovoltaics for charging, if the photovoltaics are sufficiently charged, the grid side does not act, and the energy storage battery equipment performs photovoltaic energy replenishment, if the photovoltaics are not sufficiently charged, when the grid side voltage reaches a preset range, the grid side is dispatched to provide part of the energy for energy storage charging according to a preset percentage.

5. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The reactive power compensation in step S3 is automatic compensation performed all the time.

6. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The reactive power compensation in step S3 is compensated by the inverter using a proportional-integral algorithm, and the specific calculation formula is: reactive power compensation value = Kp1×(currently output reactive power - required output reactive power)+Ki1×(currently output reactive power - required output reactive power), wherein the proportional coefficient Kp1 and the integral coefficient Ki1 are obtained through preliminary experimental tests.

7. A method for controlling low voltage in a power grid according to claim 1, characterized in that: In step S3, "using negative feedback proportional integral method to invert and supplement load to raise the voltage on the grid side" is specifically implemented as follows: Calculate the DC side current that needs to be output each time, and obtain the photovoltaic power for this energy replenishment according to the calculated current value. If the photovoltaic power is insufficient, start the energy storage battery for this energy replenishment until the grid side voltage reaches the preset range and stops this round of compensation; the calculation method of the DC side current that needs to be output is as follows; The DC side current that needs to be output this time = current voltage error value × Kp + Ki × the sum of each voltage error value in this round + the current output last time; Current voltage error value = current voltage on the grid side - stable voltage setting value; The proportional coefficient Kp and the integral coefficient Ki are obtained through preliminary experimental tests, and the default value of the last output current in the first calculation of this round is 0.

8. A method for controlling low voltage in a power grid according to claim 1, characterized in that: The method also includes step S4, systematically obtaining the underlying equipment information through the background management platform, uploading all valid data to the background storage, and displaying it to relevant personnel for review and analysis, supporting ratio adjustment, and increasing the ratio of the inverter and the energy storage battery according to the analysis results.

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