Multi-element energy storage cooperative control method for improving active support of voltage of power distribution network

Abstract

The invention provides a multi-element energy storage cooperative control method for improving active voltage support of a power distribution network, and belongs to the technical field of power distribution networks. According to the collected parameters of the power distribution network, voltage support coefficients of battery energy storage, super-capacitor energy storage and a reactive power compensation device to the power distribution network are calculated respectively; and calculating a reactive voltage support stability factor of the power distribution network, carrying out coordination control on the battery energy storage, the super-capacitor energy storage and the reactive compensation device according to a calculation result of the reactive voltage support stability factor of the power distribution network, and carrying out voltage support on the power distribution network. According to different voltage fluctuation conditions of the power distribution network, cooperative use of battery energy storage, the reactive power compensation device and super capacitor energy storage is achieved, higher stability is achieved, under the condition that renewable energy source grid connection increases day by day, control is easier, and the voltage quality problem of the power distribution network is solved more effectively.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network, and in particular relates to a multi-energy storage coordinated control method for improving active support of distribution network voltage. Background Art

[0002] With the large-scale grid connection of renewable energy sources such as wind power and photovoltaics, since most of them are generated in remote power plants, the transmission network transmits a large amount of active power to distribution networks located in different geographical areas with high-voltage technology. The distribution network delivers low-voltage or medium-voltage services to users. Since the power flow from the transmission network to the distribution network is unidirectional, and most generators in the power system are synchronous generators, the voltage regulation is mainly achieved by changing the reactive output of the generator through the excitation regulation of the generator. However, with the increase in renewable energy generation, the increase in the grid connection of power electronic equipment such as wind power, photovoltaic energy storage, grid-connected inverters, etc., the reactive power regulation of the power grid has become more difficult and complicated. Therefore, voltage stability control of the distribution network has become the key to the safe and stable operation of the current distribution network.

[0003] The equipment that supports voltage stability in the distribution network mainly includes battery energy storage, reactive power compensation devices and supercapacitors. Due to the different response speeds and energy storage capacities of the three types of equipment, different devices need to be coordinated for different voltage fluctuations in the distribution network, and it is extremely important to coordinate the coordination of the three types of equipment. There are two main methods at present. The first is to define the objective function by adopting an automatic compensation method based on a particle swarm algorithm, and to determine the harmonics and harmonic flows of reactive power components by constraining the numerical conditions of power distribution, so as to realize the electronic quantitative configuration of reactive power compensation. The second is to adopt an automatic compensation method based on sensitivity analysis, which mainly optimizes the voltage distribution of the distribution network, and compensates the reactive power of the distribution network in a targeted manner by increasing the safety margin, and selects the compensation point with the maximum sensitivity as the minimum power factor target to reduce the network loss of the distribution network. Both methods can compensate the distribution network for reactive power, but whether it is the objective function defined by the particle swarm algorithm or the method of increasing the safety margin, they are mainly based on the weak points of the distribution network voltage. The initial capacity of reactive power compensation is always large, which affects the economic operation effect of the distribution network. Summary of the invention

[0004] In view of the technical problems existing in the prior art, the present invention provides a multi-energy storage collaborative control method for improving the active support of distribution network voltage, and realizes the coordinated use of battery energy storage, reactive power compensation device and supercapacitor energy storage according to different voltage fluctuations of the distribution network to ensure the voltage stability of the distribution network.

[0005] The technical solution adopted by the present invention is: a multi-energy storage coordinated control method for improving the active support of distribution network voltage, comprising the following steps:

[0006] Collect parameters of distribution network;

[0007] Calculate the voltage support coefficient of the distribution network by the battery energy storage, supercapacitor energy storage and reactive power compensation device according to the collected parameters of the distribution network;

[0008] The reactive voltage support stability factor of the distribution network is calculated based on the voltage support coefficient of the battery energy storage, supercapacitor energy storage and reactive compensation device for the distribution network and the parameters of the distribution network. The battery energy storage, supercapacitor energy storage and reactive compensation device are coordinated and controlled based on the calculation result of the reactive voltage support stability factor of the distribution network to provide voltage support for the distribution network.

[0009] Furthermore, the parameters of the distribution network include node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, supercapacitor energy storage capacity, reactive power compensation device capacity, the number of distributed renewable energy power stations and the number of nodes.

[0010] Furthermore, the voltage support coefficient of battery energy storage for the distribution network is:

[0011]

[0012] The voltage support coefficient of supercapacitor energy storage for distribution network is:

[0013]

[0014] The voltage support coefficient of the reactive power compensation device to the distribution network is:

[0015]

[0016] Where U * n is the per-unit value of the node voltage, I * n is the per-unit value of the node current, f * is the per-unit value of frequency, T * is the per unit value of the current temperature, V * is the per unit value of wind speed, S * is the per unit value of light intensity, Q b * is the per unit value of the battery energy storage capacity, Q c * is the per-unit value of the supercapacitor energy storage capacity, Q d * is the per-unit value of the reactive power compensation device capacity, M is the number of distributed renewable energy power stations, and n is the number of nodes in the distribution network.

[0017] Furthermore, the grid reactive voltage support stability factor is:

[0018]

[0019] when When the battery energy storage and super capacitor energy storage are used to provide reactive voltage support for the distribution network, the reactive compensation device is used to adjust the voltage of the distribution network;

[0020] when When the reactive power compensation device is used to adjust the voltage of the distribution network;

[0021] when When , the distribution network voltage does not need to be compensated for reactive power.

[0022] Furthermore, the output power required by the distribution network is

[0023]

[0024] Where P G represents the unit regulation power of renewable energy generation, and θ is the phase shift angle between voltage and current.

[0025] The technical solution adopted by the present invention is also: a multi-energy storage coordinated control system for improving the active support of the distribution network voltage, including

[0026] A collection unit, used to collect parameters of the distribution network;

[0027] A calculation unit, used to calculate the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network according to the collected parameters of the distribution network; and calculate the reactive power voltage support stability factor of the distribution network according to the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network and the parameters of the distribution network;

[0028] A control unit is used to coordinate the battery energy storage, supercapacitor energy storage and reactive power compensation device according to the calculation result of the reactive voltage support stability factor of the distribution network, so as to provide voltage support for the distribution network.

[0029] The technical solution adopted by the present invention is also: a computer-readable storage medium, including a program, which can be executed by a processor to implement the multi-energy storage collaborative control method for improving the active support of distribution network voltage.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The present invention fully considers the effects of battery energy storage, supercapacitor energy storage and reactive power compensation devices on the distribution network: battery energy storage can be connected to any key node in the distribution network, can actively support the voltage of the common connection point of the distribution network, is not affected by disturbances, and can be independently operated and controlled; the power of supercapacitor energy storage has the characteristics of fast charging and discharging, which can realize millisecond-level active power and reactive power regulation, thereby realizing rapid voltage and reactive power control of the distribution network system; while using reactive power compensation devices for voltage control and reactive power balance, it can improve voltage stability, reduce voltage fluctuations and flickers. These three devices have different degrees of reactive voltage support for the distribution network, so three voltage support coefficients are calculated respectively, and the reactive voltage support stability factor is calculated based on the three voltage support coefficients. Through the calculation result of the reactive voltage support stability factor, the three devices are coordinated and controlled to provide voltage support for the distribution network and ensure the voltage stability of the distribution network.

[0032] 2. Temperature, wind speed and light intensity are the main factors affecting renewable energy generation, and reactive voltage support capacity is closely related to renewable energy generation. The present invention adds temperature, wind speed and light intensity when calculating the voltage support coefficient of battery energy storage, supercapacitor energy storage and reactive compensation devices for the distribution network, taking into account the impact of temperature, wind speed and light intensity on the distribution network.

[0033] 3. Compared with the traditional voltage stabilization control method, the present invention has higher stability. With the increasing number of renewable energy sources connected to the grid, it is easier to control and can more effectively improve the voltage quality problem of the distribution network. The voltage control efficiency is higher, and the real-time voltage of each node in the distribution network can be maintained in a stable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] The embodiment of the present invention provides a multi-energy storage coordinated control method for improving the active support of distribution network voltage, such as Figure 1 As shown, it includes the following steps:

[0037] Step 1: Collect the parameters of the distribution network; the parameters of the distribution network include node voltage U n , node current I n , frequency f, current temperature T, wind speed V, light intensity S, battery energy storage capacity Q b , supercapacitor energy storage capacity Q c , reactive power compensation device capacity Q d, the number of distributed renewable energy power stations M, and the number of nodes n.

[0038] In this embodiment, the node voltage U n =10kV, node current I n =10A, frequency f=49.9Hz, current temperature T=25℃, wind speed V=7m / s, light intensity S=10lx, battery energy storage capacity Q b =600kWh, supercapacitor energy storage capacity Q c =1000kWh, capacity of reactive power compensation device Q d =100kW.hC, the number of distributed renewable energy power stations M = 15, and the number of nodes in the distribution network n = 108.

[0039] Step 2: Calculate the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network according to the collected parameters of the distribution network.

[0040] First, calculate the per-unit value of the parameter collected in step 1 using the following formula.

[0041] U * n is the per unit value of the node voltage, U n ' is the reference value of the node voltage.

[0042] I * n is the per-unit value of the node current, I n ′ is the reference value of the node current.

[0043] f * is the per-unit value of frequency, and f′ is the reference value of frequency.

[0044] T * is the per-unit value of the current temperature, and T′ is the reference value of the temperature.

[0045] V * is the per unit value of wind speed, and V′ is the reference value of wind speed.

[0046] S * is the per unit value of light intensity, and S′ is the reference value of light intensity.

[0047] Q b * is the per unit value of the battery energy storage capacity, Q b ′ is the reference value of battery energy storage capacity.

[0048] Q c * is the per-unit value of the supercapacitor energy storage capacity, Q c ′ is the reference value of supercapacitor energy storage capacity.

[0049] Q d * is the per unit value of the reactive power compensation device capacity, Q d ’ is the reference value of the reactive power compensation device capacity.

[0050] Assume the reference value of node voltage U n ′=100V. The reference value of the node current I n ′=10A. Frequency reference value f′=10Hz. Temperature reference value T′=10℃. Wind speed reference value V′=1m / s. Light intensity reference value S′=10lx. Battery energy storage capacity reference value Q b ′=100kWh. The reference value of supercapacitor energy storage capacity Q c '=10kWh. Reference value Q of reactive power compensation device capacity d ′=10kW.hC.

[0051] Then the voltage support coefficient of battery energy storage to the distribution network is calculated as follows:

[0052]

[0053] The voltage support coefficient of supercapacitor energy storage for distribution network is:

[0054]

[0055] The voltage support coefficient of the reactive power compensation device to the distribution network is:

[0056]

[0057] Step 3: Calculate the reactive voltage support stability factor of the distribution network based on the voltage support coefficient of the distribution network provided by the battery energy storage, supercapacitor energy storage and reactive compensation device; coordinate and control the battery energy storage, supercapacitor energy storage and reactive compensation device based on the calculation result of the reactive voltage support stability factor of the distribution network to provide voltage support for the distribution network.

[0058] The grid reactive voltage support stability factor is:

[0059]

[0060] when When the reactive power output of renewable energy in the distribution network is seriously insufficient, it is necessary to use the battery energy storage and supercapacitor energy storage to support the reactive voltage of the distribution network, and use the reactive compensation device to adjust the voltage of the distribution network;

[0061] when When , it indicates that there is a certain fluctuation in the voltage in the distribution network, and the reactive power compensation device needs to be used to adjust the voltage of the distribution network;

[0062] when When , it indicates that the distribution network voltage is in a stable state, and the distribution network voltage does not need to be compensated for reactive power.

[0063] The output power required by the distribution network is

[0064]

[0065] Where P G represents the unit regulation power of renewable energy generation, and θ is the phase shift angle between voltage and current.

[0066] The voltage support coefficient of the above-mentioned battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network is brought into the calculation formula of the reactive power voltage support stability factor of the power grid:

[0067]

[0068] The calculated result of the reactive voltage support stability factor of the power grid is less than 0.5, indicating that due to the serious shortage of reactive power output of renewable energy in the distribution network, battery energy storage and supercapacitor energy storage are needed for reactive voltage support, and reactive compensation devices are used to regulate the distribution network voltage.

[0069] Calculate the required output power, assuming that the unit regulation power P of renewable energy generation G =1000kW, the phase shift angle between voltage and current θ = 30°.

[0070]

[0071] Therefore, the required battery energy storage and supercapacitor energy storage output power is 9kW.

[0072] An embodiment of the present invention further provides a multi-energy storage collaborative control system for improving active support of distribution network voltage, comprising a collection unit, a calculation unit and a control unit connected in sequence.

[0073] A collection unit, used for collecting parameters of the distribution network;

[0074] A calculation unit, used to calculate the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network according to the collected parameters of the distribution network; and calculate the reactive power voltage support stability factor of the distribution network according to the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network and the parameters of the distribution network;

[0075] A control unit is used to coordinate the battery energy storage, supercapacitor energy storage and reactive power compensation device according to the calculation result of the reactive voltage support stability factor of the distribution network, so as to provide voltage support for the distribution network.

[0076] When the system is working, the acquisition unit collects the parameters of the distribution network in real time and then transmits them to the calculation unit. The parameters include node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, supercapacitor energy storage capacity, reactive power compensation device capacity, number of distributed renewable energy power stations and number of nodes.

[0077] The calculation unit first calculates the per unit values ​​of node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, super capacitor energy storage capacity, and reactive compensation device capacity according to the reference values ​​of node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, super capacitor energy storage capacity, and reactive compensation device capacity. Then, the per unit values ​​and the number of distributed renewable energy power stations and the number of nodes are transmitted to the calculation unit to calculate the voltage support coefficients of battery energy storage, super capacitor energy storage, and reactive compensation device for the distribution network.

[0078] The voltage support coefficient of battery energy storage for the distribution network is:

[0079]

[0080] The voltage support coefficient of supercapacitor energy storage for distribution network is:

[0081]

[0082] The voltage support coefficient of the reactive power compensation device to the distribution network is:

[0083]

[0084] Finally, the current grid reactive voltage support stability factor is calculated based on the voltage support coefficient of the distribution network provided by the battery energy storage, supercapacitor energy storage and reactive compensation device, as well as the node voltage, current, battery energy storage capacity, supercapacitor energy storage capacity, per unit value of the reactive compensation device capacity, and the number of nodes, and the calculation result of the grid reactive voltage support stability factor is transmitted to the control unit.

[0085] The grid reactive voltage support stability factor is:

[0086]

[0087] The control unit determines how the battery energy storage, supercapacitor energy storage and reactive compensation device work according to the calculation result of the reactive voltage support stability factor of the distribution network, coordinates and controls the battery energy storage, supercapacitor energy storage and reactive compensation device, and provides voltage support for the distribution network.

[0088] when When the battery energy storage and super capacitor energy storage are used to support the reactive voltage of the distribution network, the reactive compensation device is used to adjust the voltage of the distribution network; the output power required by the distribution network

[0089] when When the reactive power compensation device is used to adjust the voltage of the distribution network, the output power required by the distribution network

[0090] when When , the distribution network voltage does not need to be compensated for reactive power, and the output power required by the distribution network is 0.

[0091] An embodiment of the present invention also provides a computer-readable storage medium, including a program, which can be executed by a processor to implement the multi-energy storage collaborative control method for improving the active support of distribution network voltage.

[0092] The present invention has been described in detail above through embodiments, but the contents described are only exemplary embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. Anyone who utilizes the technical solution described in the present invention, or a technician in the field, inspired by the technical solution of the present invention, designs a similar technical solution within the essence and protection scope of the present invention to achieve the above technical effects, or makes equal changes and improvements to the scope of application, etc., shall still fall within the scope of protection covered by the patent of the present invention.

Claims

1. A multi-energy storage coordinated control method for improving active support of distribution network voltage, characterized in that: The following steps are involved: Collect parameters of distribution network; Calculate the voltage support coefficient of the distribution network by the battery energy storage, supercapacitor energy storage and reactive power compensation device according to the collected parameters of the distribution network; The reactive voltage support stability factor of the distribution network is calculated based on the voltage support coefficient of the battery energy storage, supercapacitor energy storage and reactive compensation device for the distribution network and the parameters of the distribution network. The battery energy storage, supercapacitor energy storage and reactive compensation device are coordinated and controlled based on the calculation result of the reactive voltage support stability factor of the distribution network to provide voltage support for the distribution network.

2. The multi-energy storage coordinated control method for improving the active support of distribution network voltage according to claim 1 is characterized in that: The parameters of the distribution network include node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, supercapacitor energy storage capacity, reactive power compensation device capacity, the number of distributed renewable energy power stations and the number of nodes.

3. The multi-energy storage coordinated control method for improving the active support of distribution network voltage as claimed in claim 1 or 2, characterized in that: The voltage support coefficient of battery energy storage for the distribution network is: The voltage support coefficient of supercapacitor energy storage for distribution network is: The voltage support coefficient of the reactive power compensation device to the distribution network is: Where U * n is the per-unit value of the node voltage, I * n is the per-unit value of the node current, f * is the per-unit value of frequency, T * is the per unit value of the current temperature, V * is the per unit value of wind speed, S * is the per unit value of light intensity, Q b * is the per unit value of the battery energy storage capacity, Q c * is the per-unit value of the supercapacitor energy storage capacity, Q d * is the per-unit value of the reactive power compensation device capacity, M is the number of distributed renewable energy power stations, and n is the number of nodes.

4. The multi-energy storage coordinated control method for improving the active support of distribution network voltage as claimed in claim 3 is characterized in that: The grid reactive voltage support stability factor is: when When the battery energy storage and super capacitor energy storage are used to provide reactive voltage support for the distribution network, the reactive compensation device is used to adjust the voltage of the distribution network; when When the reactive power compensation device is used to adjust the voltage of the distribution network; when When , the distribution network voltage does not need to be compensated for reactive power.

5. The multi-energy storage coordinated control method for improving active support of distribution network voltage according to claim 4 is characterized in that: The output power required by the distribution network is Where P G represents the unit regulation power of renewable energy generation, and θ is the phase shift angle between voltage and current.

6. A multi-energy storage coordinated control system for improving active support of distribution network voltage, characterized in that: include A collection unit, used to collect parameters of the distribution network; A calculation unit, used to calculate the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network according to the collected parameters of the distribution network; and calculate the reactive power voltage support stability factor of the distribution network according to the voltage support coefficients of the battery energy storage, supercapacitor energy storage and reactive power compensation device for the distribution network and the parameters of the distribution network; A control unit is used to coordinate the battery energy storage, supercapacitor energy storage and reactive power compensation device according to the calculation result of the reactive voltage support stability factor of the distribution network, so as to provide voltage support for the distribution network.

7. The multi-energy storage coordinated control system for improving the active support of the distribution network voltage as claimed in claim 6 is characterized in that: The parameters of the distribution network include node voltage, current, frequency, current temperature, wind speed, light intensity, battery energy storage capacity, supercapacitor energy storage capacity, reactive power compensation device capacity, the number of distributed renewable energy power stations and the number of nodes.

8. The multi-energy storage coordinated control system for improving the active support of the distribution network voltage as claimed in claim 6 or 7, characterized in that: The voltage support coefficient of battery energy storage for the distribution network is: The voltage support coefficient of supercapacitor energy storage for distribution network is: The voltage support coefficient of the reactive power compensation device to the distribution network is: Where U * n is the per-unit value of the node voltage, I * n is the per-unit value of the node current, f * is the per-unit value of frequency, T * is the per unit value of the current temperature, V * is the per unit value of wind speed, S * is the per unit value of light intensity, Q b * is the per unit value of the battery energy storage capacity, Q c * is the per-unit value of the supercapacitor energy storage capacity, Q d * is the per-unit value of the reactive power compensation device capacity, M is the number of distributed renewable energy power stations, and n is the number of nodes.

9. The multi-energy storage coordinated control method for improving active support of distribution network voltage according to claim 8, characterized in that: The grid reactive voltage support stability factor is: when When the battery energy storage and super capacitor energy storage are used to provide reactive voltage support for the distribution network, the reactive compensation device is used to adjust the voltage of the distribution network; when When the reactive power compensation device is used to adjust the voltage of the distribution network; when When , the distribution network voltage does not need to be compensated for reactive power; The output power required by the distribution network is Where P G represents the unit regulation power of renewable energy generation, and θ is the phase shift angle between voltage and current.

10. A computer-readable storage medium, characterized in that: It includes a program that can be executed by a processor to implement the multi-energy storage collaborative control method for improving the active support of distribution network voltage as described in any one of claims 1-5.

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