CN107046290A - A Multivariate Energy Storage Fusion Method for Improving the Energy Utilization Rate of Regional Grid - Google Patents

Abstract

The invention discloses a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate, lithium battery, lead-acid accumulator, ultracapacitor, all-vanadium flow battery energy-storage units are merged applied to regional power grid system by this method, using regional power grid power prediction, energy-storage battery electricity, energy-storage battery discharge and recharge number of times as constraints, for the polynary energy-storage system configuration provides optimal policy of regional power grid system, discharge and recharge running status is strategically controlled, to improve the energy utilization rate of regional power grid system.Polynary in the regional power grid system access energy-storage units of the present invention, can effective inhibition zone network system power swing, it is to avoid regenerative resource it is abundant it is regional occur abandoning light wind-abandoning phenomenon in unbalanced power, the energy utilization rate of regional power grid system can be effectively improved.

Description

A Multivariate Energy Storage Fusion Method for Improving the Energy Utilization Rate of Regional Grid

technical field

The invention relates to the technical field of regional power grid systems, and more specifically, relates to a multi-element energy storage fusion method for improving the energy utilization rate of regional power grids.

Background technique

With policy support and technological progress, renewable energy power generation, especially wind power generation technology and wind power generation technology, has developed rapidly, and regional power grids are an important form of renewable energy utilization. Since the regional power grid contains intermittent and stochastically fluctuating renewable energy power generation affected by meteorological factors, there are power fluctuations in the regional grid-connected or isolated grid operation. The stable operation of the regional power grid mainly depends on the energy balance control. Energy storage technology is an important means to achieve energy balance and ensure the stable operation of the regional power grid. In the present invention, multi-element energy storage is connected to the regional power grid to suppress the power fluctuation of the regional power grid, avoid the phenomenon of abandoning light and wind when the power is unbalanced in areas rich in renewable energy, and can effectively improve the energy utilization rate of the regional power grid.

Contents of the invention

The technical problem to be solved by the present invention is to provide a multi-element energy storage fusion method for improving the energy utilization rate of the regional power grid.

The technical solution adopted by the present invention to solve the technical problem is: to construct a multi-element energy storage fusion method to improve the energy utilization rate of the regional power grid. The regional power grid system includes a multi-element energy storage system, a regional power grid energy storage controller and the The photovoltaic panel group and the wind power generator connected by the multiple energy storage system, the multiple energy storage system includes multiple sets of energy storage units composed of lithium batteries, lead-acid batteries, super capacitors, and all-vanadium redox flow batteries, each set of energy storage The units are all connected to the DC bus of the regional power grid through the DC/DC conversion unit, and the method includes:

The multiple energy storage system predictively controls the demanded power P _total of the regional power grid system;

The energy storage controller of the regional power grid records the charge and discharge status of each group of lithium battery energy storage units, lead-acid battery energy storage units, and all-vanadium redox flow battery energy storage units, and controls the battery energy storage units not to be allowed to discharge before they are fully charged And charging is not allowed when the discharge does not reach the allowable discharge depth;

The energy storage controller of the regional power grid records the charge and discharge times of each group of battery energy storage units, and controls the charge and discharge times ratio of the lithium battery energy storage unit, the lead-acid battery energy storage unit, and the all-vanadium redox flow battery energy storage unit to be 30: 5:130, the maximum charge and discharge times of the lithium battery energy storage unit is 3000 times, the maximum charge and discharge times of the lead-acid battery energy storage unit is 500 times, and the maximum charge and discharge times of the all-vanadium redox flow battery energy storage unit is 13000 times;

If the required power P _total of the regional power grid system is less than zero, when |p _total | is less than the maximum output power value corresponding to the remaining capacity of the supercapacitor energy storage unit When , the power of the supercapacitor energy storage unit is released first; when |p _total | is greater than And less than the maximum output power corresponding to the remaining capacity of the battery energy storage unit and When the sum of the energy storage unit of the supercapacitor and the battery energy storage unit are released; if |p _total | is greater than and The sum will release the electricity stored in the supercapacitor energy storage unit and the battery energy storage unit, and connect to the grid, and the grid will input the differential electricity of the multi-element energy storage system into the regional grid system.

In the above scheme, the multivariate energy storage system predictively controls the required power P _total of the regional power grid system including the following steps. First, the power P ₀ is given, and the actual output power P _actual of the regional power grid is detected within the time period Δt. If| P _Actual -P ₀ | is greater than 0.001W, then input the given power value P ₀ +(P _Actual -P ₀ )/△t, and perform iterative calculation until |P _Actual -P ₀ | is within 0.001W.

In the above scheme, the predicted demand power P _total of the regional grid system is divided into slowly changing demand power and fast changing demand power. The battery energy storage unit controls the slowly changing demand power, and the supercapacitor energy storage unit controls the fast changing demand power.

In the above scheme, the energy collected from the regional grid system at time t is P _n , and the energy collected from the regional grid system at time t+t ₀ is P _n+1 , if |(P _n+1 -P _n )/t ₀ | is less than 4, the battery energy storage unit controls the slowly changing demand power through charging and discharging; if |(P _n+1 -P _n )/t ₀ | is greater than 4, the supercapacitor energy storage unit controls the fast changing demand power through charging and discharging .

In the above solution, when the regional power grid energy storage controller controls the charging and discharging state of the multi-element energy storage system, when the state of charge value SOC of the supercapacitor energy storage unit does not reach 95%, discharge is not allowed and the discharge does not reach the allowable discharge Charging is not allowed when the depth is 5%; the state of charge value SOC of the lithium battery energy storage unit, lead-acid battery energy storage unit, and all-vanadium redox flow battery energy storage unit does not reach 80%, and discharge is not allowed and the discharge does not reach the allowable discharge depth of 20%. charging is not allowed.

Implementing a multivariate energy storage fusion method for improving the energy utilization rate of the regional power grid of the present invention has the following beneficial effects:

1. The present invention reasonably allocates the charging and discharging working states of the multi-element energy storage units, and the utilization rate of the multi-element energy storage units is high;

2. The multi-element energy storage unit in the regional power grid system of the present invention can effectively suppress the power fluctuation of the regional power grid system, avoid the phenomenon of abandoning light and wind when the power is unbalanced in areas rich in renewable energy, and can effectively improve the regional power grid system. energy efficiency;

3. The present invention can prolong the service life of the battery energy storage unit, and can maintain the battery energy storage unit as a whole within a unified time, reducing operating costs;

4. The invention is configured to connect to the supercapacitor energy storage unit, which can effectively suppress the large power fluctuation of the regional power grid system.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Figure 1 is a schematic diagram of the installation of the regional power grid demonstration base;

Fig. 2 is a schematic diagram of the strategy of supercapacitor energy storage unit and battery energy storage unit controlling the required power of the regional power grid system;

Figure 3 is a block diagram of the control strategy of the multi-element energy storage system.

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation manners of the present invention will now be described in detail with reference to the accompanying drawings.

The invention provides a multivariate energy storage fusion method for improving the energy utilization rate of a regional power grid. The regional power grid system includes a multivariate energy storage system, a regional power grid energy storage The energy storage system includes multiple sets of energy storage units consisting of lithium batteries, lead-acid batteries, supercapacitors, and all-vanadium redox flow batteries. Each set of energy storage units is connected to the DC bus of the regional power grid through a DC/DC conversion unit. Taking a regional power grid demonstration base as an example, as shown in Figure 1, it is equipped with a photovoltaic power generation system and a wind power generation system, of which the photovoltaic capacity is 100kW, the wind power generation capacity is 50kW, and it is equipped with a 5kW supercapacitor energy storage system and a 10kW lead-acid battery energy storage system. system, 15kW lithium iron phosphate battery energy storage system, 20kW all-vanadium redox flow battery energy storage system and 100kW load. The allocation method is: configure 5 sets of supercapacitor energy storage units with a capacity of 1kW each, configure 5 sets of lead-acid battery energy storage units with a capacity of 2kW each, configure 5 sets of lithium iron phosphate battery energy storage units with a capacity of 3kW each, and configure 2 sets of 10kW all-vanadium redox flow battery energy storage unit and 100kW load each. Each group of energy storage units is connected to the DC bus of the regional power grid through a DC/DC module. The multivariate energy storage fusion method includes:

The multi-element energy storage system performs predictive control on the demanded power P _total of the regional power grid system. Specifically, the following control method is adopted: the power P ₀ is given first, and the actual output power P _actual of the regional power grid is detected within the time period Δt. If |P _actual -P ₀ | is greater than 0.001W, then input the given power value as P ₀ +(P _actual -P ₀ )/△t, and perform iterative calculation until |P _actual -P ₀ | is within 0.001W.

The predicted demand power P _total of the regional power grid system is divided into slowly changing demand power and fast changing demand power. The battery energy storage unit controls the slowly changing demand power; the super capacitor energy storage unit controls the fast changing demand power. For example, when the demand power P _total of the regional power grid system has huge power fluctuations, the super capacitor energy storage unit is put into operation first, absorbing or releasing electric energy In order to stabilize the power quality fluctuation of the regional power grid system, referring to Figure 2, the energy of the regional power grid system collected at time t is P _n , and the energy of the regional power grid system collected at time t+t ₀ is P _n+1 , if |(P _{n+ 1} -P _n )/t ₀ | is less than 4, the battery energy storage unit slowly changes the required power through charge and discharge control; if |(P _n+1 -P _n )/t ₀ | is greater than 4, the supercapacitor energy storage unit The fast-changing demand power is controlled by charging and discharging.

The regional grid energy storage controller records the charge and discharge status of each group of lithium battery energy storage units, lead-acid battery energy storage units, and all-vanadium redox flow battery energy storage units. According to the state of charge and discharge (SOC) of each lithium battery energy storage unit, lead-acid battery energy storage unit, and all-vanadium redox flow battery energy storage unit, its working state is reasonably configured to make it work within the optimal operating range. Specifically, the following control methods are adopted: when the state of charge value SOC of the supercapacitor energy storage unit does not reach 95%, discharge is not allowed, and when the discharge does not reach the allowable discharge depth of 5%, charging is not allowed; lithium battery energy storage units, lead-acid battery energy storage units 1. When the state of charge value SOC of the all-vanadium redox flow battery energy storage unit does not reach 80%, it is not allowed to discharge and the discharge does not allow charging when the discharge does not reach the allowable discharge depth of 20%.

The energy storage controller of the regional grid records the charging and discharging times of each group of battery energy storage units, and according to the charging and discharging times of each group of lithium battery energy storage units, lead-acid storage battery Working state, make it work in the best operating range. Specifically, the following control methods are adopted: the ratio of charging and discharging times of lithium battery energy storage unit, lead-acid battery energy storage unit, and all-vanadium redox flow battery energy storage unit is 30:5:130, and the maximum charging and discharging times of lithium battery energy storage unit is 3000 times, the maximum charge and discharge times of the lead-acid battery energy storage unit is 500 times, and the maximum charge and discharge times of the all-vanadium redox flow battery energy storage unit is 13000 times.

The multi-energy storage control strategy of the regional power grid is based on multi-objective optimization operation. The optimization objectives include the maximum new energy consumption capacity, the minimum charge and discharge times of the multi-energy storage system, and the minimum operating cost of the regional power grid system. The number of groups can vary according to different operating objectives.

Figure 3 is a block diagram of the control strategy of the multi-element energy storage system, which lists the corresponding energy storage charge and discharge control strategies in 54 different states, where the numbers outside the box in the figure indicate the number of possible occurrences of the output strategy in the 54 states. The number "1" in the box indicates that the regional grid system's demand for multiple energy storage systems is discharge and The number "2" indicates that the regional grid system's demand for multiple energy storage systems is discharge and The number "3" indicates that the regional power grid system's demand for multiple energy storage systems is discharge and The number "4" indicates that the regional grid system's demand for multiple energy storage systems is discharge and The number "5" indicates that the regional power grid system's demand for multiple energy storage systems is discharge and The number "6" indicates that the regional grid system's demand for multiple energy storage systems is discharge and The letter "a" indicates that the battery SOC is lower than the lower limit; the letter "b" indicates that the battery SOC is in normal working condition; the letter "c" indicates that the battery SOC is higher than the upper limit. The letter "d" indicates that the SOC of the supercapacitor is lower than the lower limit; the letter "e" indicates that the SOC of the supercapacitor is in a normal working state; the letter "f" indicates that the SOC of the supercapacitor is higher than the upper limit. Among them: P _total represents the demand power of the regional power grid system for the multi-element energy storage system; Indicates that the supercapacitor energy storage unit that is allowed to discharge corresponds to the maximum output power; Indicates that the remaining capacity of the battery energy storage unit that is allowed to discharge corresponds to the maximum output power; Indicates the maximum input power of the supercapacitor energy storage unit that is allowed to be charged; Indicates the maximum input power of the battery energy storage unit that is allowed to charge. P _w is the sum of the power generated by the regional grid system, and P _boi is the sum of the power consumed by the load.

If the required power P _total of the regional grid system is less than zero, when |p _total | is less than the maximum output power value corresponding to the remaining capacity of the supercapacitor energy storage unit When , the power of the supercapacitor energy storage unit is released first; when |p _total | is greater than And less than the maximum output power corresponding to the remaining capacity of the battery energy storage unit and When the sum of the energy storage unit of the supercapacitor and the battery energy storage unit are released; if |p _total | is greater than and The sum will release the electricity stored in the supercapacitor energy storage unit and the battery energy storage unit, and connect to the grid, and the grid will input the differential electricity of the multi-element energy storage system into the regional grid system.

Embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementations, and the above-mentioned specific implementations are only illustrative, rather than restrictive, and those of ordinary skill in the art will Under the enlightenment of the present invention, many forms can also be made without departing from the gist of the present invention and the protection scope of the claims, and these all belong to the protection of the present invention.

Claims (5)

1. a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate, the regional power grid system includes polynary storage Energy system, regional power grid energy storage controller and the photovoltaic panel group being connected with the polynary energy-storage system and wind-driven generator, it is described Polynary energy-storage system includes multigroup energy storage separately constituted by lithium battery, lead-acid accumulator, ultracapacitor, all-vanadium flow battery Unit, every group of energy-storage units are all connected to regional power grid dc bus by DC/DC converter units, it is characterised in that the side Method includes：

Demand power P of the polynary energy-storage system to regional power grid system_totalIt is predicted control；

The regional power grid energy storage controller records every group of lithium battery energy storage battery unit, lead-acid accumulator energy-storage units, all-vanadium flow The charging and discharging state of battery energy storage unit, control battery energy storage unit does not allow electric discharge and in electric discharge before not fully charged Do not allow charging when being not reaching to permission depth of discharge；

Discharge and recharge number of times of the regional power grid energy storage controller record per Battery pack energy-storage units, controls lithium battery energy storage battery list Member, the discharge and recharge number of times ratio of lead-acid accumulator energy-storage units, all-vanadium flow battery energy-storage units are 30:5:130, lithium battery storage The maximum discharge and recharge number of times of energy unit is 3000 times, and the maximum discharge and recharge number of times of lead-acid accumulator energy-storage units is 500 times, Quan Fan The maximum discharge and recharge number of times of flow battery energy storage unit is 13000 times；

If the demand power P of the regional power grid system_totalLess than zero, | p_total| it is remaining less than ultracapacitor energy storage unit Capacity correspondence peak power output valueWhen, then first discharge ultracapacitor energy storage unit electricity；| p_total| it is more than And less than battery energy storage unit residual capacity correspondence peak power outputWithDuring sum, then ultracapacitor is discharged Energy-storage units and the electricity of battery energy storage unit storage；If | p_total| it is more thanWithSum, then discharge ultracapacitor Energy-storage units and the electricity of battery energy storage unit storage, and power network is connected, power network is defeated by the difference electricity of polynary energy-storage system Enter regional power grid system.

2. a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate according to claim 1, its feature It is, the demand power P of the polynary energy-storage system PREDICTIVE CONTROL regional power grid system_totalComprise the following steps, first give work( Rate P₀, regional power grid real output P is detected in period △ t_{It is actual}If, | P_{It is actual}-P₀| it is more than 0.001W, then then defeated Enter given performance number for P₀+(P_{It is actual}-P₀)/△ t, are so iterated calculating until | P_{It is actual}-P₀| in 0.001W.

3. a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate according to claim 2, its feature It is, predicts obtained regional power grid system demand power P_totalIt is divided into gradual demand power and fast change demand power, battery storage Can the gradual demand power of unit control, the fast change demand power of ultracapacitor energy storage unit control.

4. a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate according to claim 3, its feature It is, is P in the energy of t pickup area network system_n, in t+t₀The energy of moment pickup area network system is P_n+1, If | (P_n+1-P_n)/t₀| less than 4, then battery energy storage unit passes through the gradual demand power of charge and discharge control；If | (P_n+1-P_n)/t₀| More than 4, then ultracapacitor energy storage unit becomes demand power soon by charge and discharge control.

5. a kind of polynary energy storage fusion method for improving regional power grid energy utilization rate according to claim 1, its feature It is, when the regional power grid energy storage controller controls the charging and discharging state of the polynary energy-storage system, ultracapacitor energy storage The state-of-charge value SOC of unit does not allow to discharge when being not reaching to 95% and discharged when being not reaching to permission depth of discharge 5% not Allow charging；Lithium battery energy storage battery unit, lead-acid accumulator energy-storage units, the state-of-charge value of all-vanadium flow battery energy-storage units SOC be not reaching to 80% do not allow to discharge and discharge be not reaching to permission depth of discharge 20% when do not allow charging.