Distributed photovoltaic power generation energy management and control method

Abstract

The invention relates to a distributed photovoltaic power generation energy management and control method, which comprises the following steps of: 1, reversely sending photovoltaic electric quantity which cannot be consumed to a high-voltage side by using a station transformer; and step 2, installing anti-countercurrent devices on a working incoming line and a standby incoming line of the factory high-voltage bus respectively, and calculating active power in real time according to incoming line current and bus voltage to judge whether photovoltaic electric quantity is transmitted to a power grid or not. And step 3, reasonably setting constant values of the anti-reflux devices arranged in the working incoming line and the standby incoming line of the station high-voltage bus in the step 2, and judging whether the condition of reverse power occurs, indicating that the high-voltage station system cannot absorb all photovoltaic electric quantity, and tripping off a photovoltaic power switch by the protection action of the anti-reflux devices so as to effectively control and distribute electric energy. According to the invention, the photovoltaic power which cannot be consumed can be transmitted back to the high-voltage side by means of the station transformer, so that the purpose of completely consuming the power is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrical equipment and relates to an energy management method, in particular to a distributed photovoltaic power generation energy management method. Background Art

[0002] In recent years, with the development of new energy, power plants have taken advantage of their respective geographical environments to build distributed photovoltaic projects to save power.

[0003] The electricity generated by small-scale distributed photovoltaic projects must be used by the company itself, and any surplus electricity will not be connected to the grid.

[0004] At present, photovoltaic power is generally connected to the low-voltage distribution network. Due to improper selection of access points or load changes, the power cannot be absorbed.

[0005] Since there is no dedicated step-up transformer, the power flow distribution cannot be changed, resulting in low equipment utilization hours and the photovoltaic power availability cannot meet expectations.

[0006] Therefore, in order to solve the above technical problems, the present invention proposes a distributed photovoltaic power generation energy management method.

[0007] After searching, no public documents of the prior art identical or similar to the present invention were found. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and to propose a distributed photovoltaic power generation energy management method, which can use the factory transformer to send the photovoltaic power that cannot be absorbed back to the high-voltage side to achieve the purpose of absorbing all the power.

[0009] The present invention solves the practical problem by adopting the following technical solutions:

[0010] A distributed photovoltaic power generation energy management and control method comprises the following steps:

[0011] Step 1: Use the factory transformer to send the unabsorbed photovoltaic power back to the high-voltage side;

[0012] Step 2: Install anti-backflow devices on the working incoming line and standby incoming line of the high-voltage busbar in the factory, and calculate the active power in real time based on the incoming line current and busbar voltage to determine whether the photovoltaic power is fed into the grid.

[0013] Step 3: Reasonably set the setting value of the anti-backflow device installed on the working and standby incoming lines of the high-voltage busbar in step 2 to determine if reverse power occurs, indicating that the high-voltage plant system can no longer absorb all photovoltaic power. The anti-backflow device protection will trip the photovoltaic power switch, thereby achieving effective control and distribution of electrical energy.

[0014] Moreover, the specific method of step 1 is:

[0015] Calculate the maximum capacity of photovoltaic power and the capacity of the plant high-voltage system, select the plant high-voltage load section that can meet the full power consumption, so that the photovoltaic power generation can be fully consumed. Without a specially configured step-up transformer, the surplus photovoltaic power that cannot be consumed can be borrowed by borrowing the existing plant low-voltage distribution network transformer, changing the power flow distribution, and transferring the surplus power from the low-voltage side of the transformer to the high-voltage side, and supplying it to the high-voltage plant section for consumption. The anti-backflow device originally installed in the low-voltage distribution section incoming line circuit is cancelled, and the photovoltaic surplus power is reversed to the plant high-voltage busbar through the low-voltage distribution network, so that the surplus photovoltaic power that cannot be consumed is reversed to the plant high-voltage side.

[0016] Moreover, the specific method of step 2 is:

[0017] The active power is calculated in real time based on the incoming current and bus voltage, and the positive and negative conditions of the active power during normal operation are used to determine whether the photovoltaic power is fed into the grid.

[0018] Moreover, the anti-backflow device in step 3 should meet the following conditions at the same time:

[0019] Condition 1: The access switch is in the closed position;

[0020] Condition 2: The reverse power protection function soft pressure plate is put into use;

[0021] Condition 3: PT disconnection lockout;

[0022] Condition 4: Active power is reversed and the value of active power is greater than the fixed value.

[0023] When the above conditions are met at the same time, the protection output will be activated after a delay.

[0024] Advantages and beneficial effects of the present invention:

[0025] 1. The present invention provides a distributed photovoltaic power generation energy management method. By calculating the actual usage capacity of small-scale distributed photovoltaic power, a plant-use high-voltage load section that can meet the total power consumption is selected to make up for the shortcomings of photovoltaic power that cannot be consumed and low equipment utilization hours.

[0026] 2. According to the characteristics of electrical connection, when the low-voltage distribution network cannot absorb the electricity, the present invention uses a factory transformer to change the flow distribution of the remaining electricity and sends it back to the high-voltage side, so as to achieve the purpose of absorbing all the electricity.

[0027] 3. The present invention moves the power judgment point forward to the load side of the plant high-voltage bus power switch (working switch and standby switch), installs an anti-backflow device, calculates the power direction in real time, and when the high-voltage plant power cannot absorb the photovoltaic power, the anti-backflow protection action trips the photovoltaic power switch, thereby achieving the purpose of "self-generation for self-use, and no surplus power is connected to the grid". BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a processing flow chart of the distributed control method of the present invention;

[0029] Figure 2 This is the logic diagram of the anti-backflow protection action of the present invention. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

[0031] A distributed photovoltaic power generation energy management method, such as Figure 1 As shown, the following steps are included:

[0032] Step 1: Use the factory transformer to send the unabsorbed photovoltaic power back to the high-voltage side;

[0033] The specific method of step 1 is:

[0034] Calculate the maximum capacity of photovoltaic power and the capacity of the high-voltage system for the plant, select the high-voltage load section for the plant that can meet the full power consumption, so that the photovoltaic power generation can be fully consumed. Without a special step-up transformer, the surplus photovoltaic power that cannot be consumed can be transferred from the low-voltage side of the transformer to the high-voltage side by using the existing low-voltage distribution network transformer for the plant, changing the power flow distribution, and supplying the high-voltage plant section for consumption. The anti-backflow device originally installed in the incoming line circuit of the low-voltage distribution section is cancelled, and the surplus photovoltaic power is reversed to the plant high-voltage busbar through the low-voltage distribution network, so that the surplus photovoltaic power that cannot be consumed is reversed to the high-voltage side of the plant;

[0035] Step 2: Install anti-backflow devices on the working incoming line and standby incoming line of the high-voltage busbar in the factory, and calculate the active power in real time based on the incoming line current and busbar voltage to determine whether the photovoltaic power is fed into the grid.

[0036] The specific method of step 2 is:

[0037] The active power is calculated in real time based on the incoming current and bus voltage, and the positive and negative conditions of the active power during normal operation are used to determine whether the photovoltaic power is fed into the grid.

[0038] Step 3: Reasonably set the setting value of the anti-backflow device installed on the working incoming line and standby incoming line of the high-voltage busbar in step 2 to judge if reverse power occurs, indicating that the high-voltage plant system can no longer absorb all the photovoltaic power. The anti-backflow device protection will trip the photovoltaic power switch, thereby achieving effective control and distribution of electrical energy and greatly improving energy utilization efficiency.

[0039] like Figure 2 As shown, the setting of the anti-backflow device in step 3 should meet the following conditions at the same time:

[0040] Condition 1: The access switch is in the closed position;

[0041] Condition 2: The reverse power protection function soft pressure plate is put into use;

[0042] Condition 3: PT disconnection lockout;

[0043] Condition 4: Active power is reversed and the value of active power is greater than the fixed value.

[0044] When the above conditions are met at the same time, the protection output will be activated after a delay.

[0045] Embodiment 1:

[0046] 1. During the standby period of the calculated unit, the 6kV plant power consumption is greater than the photovoltaic grid-connected power, and the photovoltaic power generation can be fully absorbed.

[0047] 2. The anti-backflow device originally installed in the working incoming line circuit of the low-voltage distribution section is cancelled, and the photovoltaic surplus power is fed back to the 6kV bus through the low-voltage distribution 400V network.

[0048] 3. Anti-backflow devices are installed on the working incoming line and the standby incoming line on the 6kV side, and the power is calculated in real time using the incoming line current and bus voltage.

[0049] 4. Reasonably set the protection setting value of the anti-backflow device.

[0050] 5. When the 6kV factory power cannot absorb the photovoltaic power, the anti-backflow device protection will trip the photovoltaic power switch, achieving the purpose of "self-generation for self-use, and no surplus power will be connected to the grid".

[0051] The method of the present invention has been put into use. Under the premise of meeting the photovoltaic power consumption, the operation mode of the low-voltage power supply system is adjusted more reasonably, which can maximize the safety and economy. It will be applied to the transformation of other units of the same type in the future.

[0052] It should be emphasized that the embodiments of the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation modes. Any other implementation modes derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A distributed photovoltaic power generation energy management and control method, characterized in that: The following steps are involved: Step 1: Use the factory transformer to send the unabsorbed photovoltaic power back to the high-voltage side; Step 2: Install anti-backflow devices on the working incoming line and standby incoming line of the high-voltage busbar in the factory, and calculate the active power in real time based on the incoming line current and busbar voltage to determine whether the photovoltaic power is fed into the grid; Step 3: Reasonably set the setting value of the anti-backflow device installed on the working and standby incoming lines of the high-voltage busbar in step 2 to determine if reverse power occurs, indicating that the high-voltage plant system can no longer absorb all photovoltaic power. The anti-backflow device protection will trip the photovoltaic power switch, thereby achieving effective control and distribution of electrical energy.

2. A distributed photovoltaic power generation energy management and control method according to claim 1, characterized in that: The specific method of step 1 is: Calculate the maximum capacity of photovoltaic power and the capacity of the plant high-voltage system, select the plant high-voltage load section that can meet the full power consumption, so that the photovoltaic power generation can be fully consumed. Without a specially configured step-up transformer, the surplus photovoltaic power that cannot be consumed can be borrowed by borrowing the existing plant low-voltage distribution network transformer, changing the power flow distribution, and transferring the surplus power from the low-voltage side of the transformer to the high-voltage side, and supplying it to the high-voltage plant section for consumption. The anti-backflow device originally installed in the low-voltage distribution section incoming line circuit is cancelled, and the photovoltaic surplus power is reversed to the plant high-voltage busbar through the low-voltage distribution network, so that the surplus photovoltaic power that cannot be consumed is reversed to the plant high-voltage side.

3. A distributed photovoltaic power generation energy management and control method according to claim 1, characterized in that: The specific method of step 2 is: The active power is calculated in real time based on the incoming current and bus voltage, and the positive and negative conditions of the active power during normal operation are used to determine whether the photovoltaic power is fed into the grid.

4. A distributed photovoltaic power generation energy management and control method according to claim 1, characterized in that: The anti-backflow device in step 3 should meet the following conditions at the same time: Condition 1: The access switch is in the closed position; Condition 2: The reverse power protection function soft pressure plate is put into use; Condition 3: PT disconnection lockout; Condition 4: Active power is reversed and the value of active power is greater than the set value; When the above conditions are met at the same time, the protection output will be activated after a delay.

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