CN117559391A - Hybrid energy storage joint planning method considering flexible supply-demand balance of power system - Google Patents

Hybrid energy storage joint planning method considering flexible supply-demand balance of power system Download PDF

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CN117559391A
CN117559391A CN202311404402.3A CN202311404402A CN117559391A CN 117559391 A CN117559391 A CN 117559391A CN 202311404402 A CN202311404402 A CN 202311404402A CN 117559391 A CN117559391 A CN 117559391A
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flexibility
power
unit
thermal power
energy storage
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何义琼
刘建飞
王俊生
刘宏扬
康赫然
张昭
胡文波
张天闻
于啸宇
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State Grid Corp of China SGCC
Northeast Electric Power University
Economic and Technological Research Institute of State Grid Inner Mongolia Electric Power Co Ltd
State Grid Eastern Inner Mongolia Power Co Ltd
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State Grid Corp of China SGCC
Northeast Dianli University
Economic and Technological Research Institute of State Grid Inner Mongolia Electric Power Co Ltd
State Grid Eastern Inner Mongolia Power Co Ltd
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    • H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
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    • H02J2300/28—The renewable source being wind energy

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Abstract

The invention discloses a hybrid energy storage joint planning method considering the flexible supply-demand balance of a power system, which specifically comprises the following steps: according to the time sequence coupling characteristics of the waste wind generated by insufficient peak regulation of the conventional unit and the power transmission blocking waste wind under the same time sequence, calculating total waste wind; defining the system flexibility requirement as the system adjustment capability required by dealing with the change of the net load uncertainty, and calculating the difference value between the flexibility supply and the requirement in the same time period by combining the flexibility transformation of the thermal power unit, the pumped storage and the flexibility supply capability of the vanadium redox flow battery; establishing a thermal power unit flexibility transformation and hybrid energy storage double-layer planning model considering flexibility by combining total abandoned wind and the difference value of flexibility supply and demand in the same time period; and solving a double-layer planning model by adopting an NSGA-III algorithm to obtain a thermal power unit flexibility transformation and hybrid energy storage configuration scheme. The economy and flexibility of each energy storage scheme are compared from multiple angles, and the energy storage system has better economic and environmental benefits.

Description

Hybrid energy storage joint planning method considering flexible supply-demand balance of power system
Technical Field
The invention belongs to the technical field of power system planning, and particularly relates to a hybrid energy storage joint planning method considering power system flexibility supply-demand balance.
Background
The output of new energy sources such as wind and light has strong randomness and volatility, so that the flexibility requirement of the system is greatly increased. The thermal power unit is turned off successively under the 'double-carbon' target, and the flexibility requirement of the power system is difficult to meet only by considering the method for modifying the flexibility of the thermal power unit.
Disclosure of Invention
The invention aims to provide a hybrid energy storage joint planning method considering the flexible supply-demand balance of an electric power system, designs a thermal power unit flexible transformation and hybrid energy storage double-layer planning model considering flexibility, and has better economic and environmental benefits by considering carbon emission constraint.
The technical scheme adopted by the invention is that the hybrid energy storage joint planning method considering the flexible supply-demand balance of the power system is implemented according to the following steps:
step 1, calculating total abandoned wind according to time sequence coupling characteristics of abandoned wind and power transmission blocking abandoned wind generated by insufficient peak shaving of a conventional unit under the same time sequence;
step 2, defining the system flexibility requirement as the system adjustment capability required by dealing with the change of the net load uncertainty, and calculating the difference between the flexibility supply and the requirement in the same time period by combining the flexibility transformation of the thermal power unit, the pumped storage and the flexibility supply capability of the vanadium redox flow battery;
Step 3, establishing a thermal power unit flexibility transformation and hybrid energy storage double-layer planning model considering flexibility by combining total abandoned wind and the difference value of flexibility supply and demand in the same time period;
and 4, solving a double-layer planning model by adopting an NSGA-III algorithm to obtain a thermal power unit flexibility transformation and hybrid energy storage configuration scheme.
The invention is also characterized in that:
the specific process of the step 1 is as follows:
after wind power with strong fluctuation and anti-peak shaving characteristics is connected into a power grid in a large scale, as the conventional thermal power generating unit is difficult to quickly respond to wind power output fluctuation, the capacity of the system for receiving wind power is exceeded, peak shaving deficiency wind discarding is generated, and the wind discarding expression is as follows:
wherein: p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) W (t) is the wind power at time t; p (P) FR (t) is the wind power acceptable by the system at the moment t;
the expression of the wind curtailment due to the power transmission line conveyance blockage is:
wherein: p (P) LT (t) delivering blocking wind-abandoning power at t time; p (P) LM Maximum power transmission capacity for the power transmission line; p (P) W (t) is the wind power at time t;
the conventional unit peak regulation insufficient waste wind and conveying blockage waste wind under the same time sequence obtained by the calculation formula (1) and the calculation formula (2) are calculated to obtain total waste wind, wherein the calculation formula is as follows:
P L (t)＝max{P LG (t),P LT (t)} (3)
Wherein: p (P) L (t) is the total wind curtailed power at time t; p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) LT And (t) delivering blocking wind-discarding power at t time.
The specific process of the step 2 is as follows:
step 2.1, system flexibility requirement F n,t Defined as coping with payload P J Varying the tuning capabilities that flexible resources within the system can provide:
F n,t ＝P J,t+1 -P J,t (4)
wherein F is n,t The flexibility requirement of the system at the moment t; p (P) J,t And P J,t+1 The net loads at the time t and the time t+1 of the system are respectively represented;
P J,t ＝P Load,t -P RE,t (5)
wherein P is RE,t For the power of new energy sources such as wind at t moment, P Load,t The load at the moment t; p (P) J,t Indicating the net at system time tA load;
by the formulas (4) and (5), the uncertainty of the source load is quantized into the flexibility adjustment capability required by the power system in a certain time scale, and then the system flexibility requirement at the moment t is as follows:
in the method, in the process of the invention,and->The system up-regulation flexibility requirement and the down-regulation flexibility requirement at the moment t are respectively;
step 2.2, the flexibility transformation supply capacity expression of the thermal power generating unit is as follows:
in the method, in the process of the invention,and->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation; p (P) j,max The maximum output before the thermal power unit is flexibly modified; p (P) j*,min Respectively the minimum output after the thermal power unit is flexibly modified; / >Modifying the downward climbing rate of the thermal power unit g for flexibility; />Modifying the upward climbing speed of the thermal power unit g for flexibility; τ is the time scale;
the flexibility of pumped storage is given by the following expression:
in the method, in the process of the invention,the upward and downward flexibility adjusting capability of the pumped storage is respectively provided; p (P) st,+,max 、P st,-,max Respectively pumping and storing the maximum power generation and the water storage power; s is S t 、S max 、S min The upper limit and the lower limit of the water storage capacity and the water storage capacity at the moment t are respectively; delta is the climbing time interval;
the flexible supply capacity expression of the vanadium liquid flow is as follows:
wherein:and->The upward and downward flexibility supply capacity of the all-vanadium redox flow battery is respectively provided;is the actual state of charge of the flow battery; />The maximum charge state and the minimum charge state of the flow battery are respectively; e (E) VRB Is the rated capacity of the flow battery; p (P) + (t) and P- (t) are respectively the charge and discharge power of the flow battery; η (eta) in And eta out The charge and discharge efficiency of the flow battery are respectively; τ is the time scale;
step 2.3, the capability of the unit for increasing the power generation rate is upward power generation, and the capability for reducing the power generation rate is downward power generation; in the same direction, the difference between the flexibility supply and demand in the same time period is defined as the system flexibility margin F MAR,t The expression is:
F MAR,t ＝F S,t -F n,t (11)
wherein F is S,t Represents the flexible provisioning capability that flexible resources within the system can provide;and->Is the up and down flexibility margin that the system can provide; />Upward flexibility adjustment capability provided for renewable energy sources; />The ability to adjust the downward flexibility provided for demand response; />Respectively is a mixed storageThe upward and downward flexibility adjustment capability provided by the system can be provided; />Respectively the upward and downward flexibility requirements; />And->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation;the upward and downward flexibility adjusting capability of the pumped storage is respectively provided; />And->Respectively, the upward and downward flexibility supply capacity of the all-vanadium redox flow battery.
The double-layer planning model in the step 3 comprises an upper-layer economy model objective function which takes the lowest comprehensive cost as an optimization target, takes the capacity and the grid-connected position of the hybrid energy storage as decision variables of the model, and further comprises a lower-layer flexibility model objective function which takes the minimum flexibility punishment cost and the maximum carbon income as targets, wherein the decision variables are the output power of flexible resources such as a system power supply unit, the hybrid energy storage and the like, and constraint conditions.
The upper layer economic model objective function is:
minC 1 ＝C K +C S +C H +C T -R t (13)
Wherein C is 1 Integrated cost for system；C K The comprehensive operation cost of the system comprises punishment cost of demand response and construction and operation maintenance cost of a conventional thermal power generating unit; c (C) T The cost of wind disposal is the cost; p (P) e (t) is the wind-abandoning power absorbed by the energy storage at the moment t; mu (mu) T The wind power penalty value is discarded per unit; t (T) S Planning a period; c (C) H 、C s The investment cost and the operation and maintenance cost of the pumped storage and all-vanadium redox flow battery are respectively; r is R t Generating benefits for the thermal power generating unit;
the pumped storage cost comprises the construction cost of the newly added pumped storage unit and the operation and maintenance cost of the pumped storage unit, and is expressed as:
C H ＝P H K H +E H k H /n H (14)
wherein C is H The new construction cost and the operation and maintenance cost are used for pumped storage; p (P) H 、k H The capacity of the total assembly machine of the pumped storage unit and the operation and maintenance cost coefficient thereof are respectively; e (E) H The new pumping energy storage capacity is built; k (k) H The construction cost coefficient of pumped storage; n is n H The operation life of the pump is stored;
assuming that all the vanadium redox flow batteries are newly built, the cost comprises investment cost and operation and maintenance cost, the investment cost main body of the all the vanadium redox flow batteries is the battery cost, and the cost C of the all the vanadium redox flow batteries is calculated according to the rated capacity s Expressed as:
C s ＝E es k es (m s /n s +ν) (15)
wherein C is S Is the total cost of the all-vanadium redox flow battery; e (E) es The capacity of the vanadium redox flow battery is newly increased; k (k) es The construction cost coefficient of the vanadium redox flow battery is the construction cost coefficient of the vanadium redox flow battery; m is m s 、n s The times of charging and discharging of the all-vanadium redox flow battery and the total times of chargeable and dischargeable times in the whole life cycle are respectively; v is the operation and maintenance cost coefficient of the all-vanadium redox flow battery;
the generating income of the thermal power generating unit comprises the network electric quantity income of the power grid company for the thermal power generating unit and the operation compensation cost of the power grid for the thermal power generating unit participating in the flexibility improvement, and the concrete expression is as follows:
wherein R is t Generating benefits for the thermal power generating unit;F G the method comprises the steps of respectively compensating the network-surfing electric quantity income of the thermal power generating unit and the operation compensation cost of the thermal power generating unit; w (W) G,i The method comprises the steps of surfing the internet for the ith unit; c (C) fit The method is characterized in that the internet electricity price of thermal power generation is achieved; p (P) G,i (t) is the power of the ith unit at the moment t; c (C) pr,GP The compensation unit price is modified for the flexibility of the thermal power generating unit; t is t 1 The time period is modified for the flexibility of the thermal power generating unit; p (P) a,i The minimum output of the conventional peak shaving stage of the ith unit is obtained;
the underlying flexible model objective function is as follows:
wherein C is MAR Penalty costs for inflexibility; beta down 、β up Respectively representing downward and upward flexibility deficiency punishment coefficients;and->Is the up and down flexibility margin that the system can provide; a, a c A fee for the carbon trade; b (B) c Is carbon yield; e, e c CO produced by combustion of coal of unit mass 2 Is a conversion coefficient of (a); e (E) RE,t Generating energy for new energy; θ c Coal consumption for producing unit electric energy;
the formula of the thermal power generating unit flexibility transformation cost is as follows:
C F ＝O g (P a -P j*,min ) (20)
wherein C is F The cost is improved for the flexibility of the thermal power generating unit;the lower limit of the output after the flexibility modification of the thermal power unit j is set; o (O) g The unit cost for the flexible reconstruction of the thermal power generating unit is realized; p (P) a The lower limit of the output before the thermal power unit is flexibly modified.
The constraint conditions are specifically as follows:
electric quantity balance constraint:
W g +W w -ΔW w ≥W L (21)
in which W is g 、W w 、ΔW w 、W L The method comprises the steps of generating capacity, wind power generating capacity, wind discarding capacity and load capacity of the thermal power generating unit respectively;
pumped storage reservoir capacity constraint and daily clearance constraint:
wherein E is H,i Drawing the water storage capacity of the power storage station at the moment i; e (E) H,min 、E H,max Sequentially the minimum water storage capacity and the maximum water storage capacity of the upper reservoir of the pumping and storage power station; η (eta) pump 、η gen Pumping water and generating power respectively; t (T) S Is a unit time; mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0; p (P) p,i Real-time power of the pump storage unit at the moment i;
output constraint of pumped storage unit
Wherein alpha is H Pumping/storing time from dead water level to full water level or from full water level to dead water level for the pumped storage unit under rated power; e (E) eH Rated water storage capacity of the upper reservoir is pumped and stored; p (P) p,i Real-time power of the pump storage unit at the moment i; e (E) H,min 、E H,max Sequentially the minimum water storage capacity and the maximum water storage capacity of the upper reservoir of the pumping and storage power station;
all-vanadium redox flow battery power constraint:
in the method, in the process of the invention,respectively the minimum value and the maximum value of the power of the all-vanadium redox flow battery, P e,t The power at the moment t of the vanadium redox flow battery; />And->E is the minimum value and the maximum value of the capacity of the all-vanadium redox flow battery e,t Is the capacity of the vanadium redox flow battery in a time period t;
carbon emission constraint:
in the method, in the process of the invention,maximum carbon emission for the t-th year; mu (mu) g Is the carbon emission rate; e (E) g,t Generating energy for a thermal power generating unit of the t year;
flexible supply and demand balance constraint:
F S,t +F FG,t +F N,t +|F MAR,t |≥|F n,t | (29)
wherein F is S,t 、F FG,t And F N,t Flexibility supply capability for the hybrid energy storage system, the thermal power flexibility transformation and the demand response respectively; f (F) MAR,t A margin of system flexibility; f (F) n,t Is a system flexibility requirement;
system power balance constraint:
wherein: mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0;is a variable of 0-1 and satisfies +.> The method comprises the steps of (1) marking an electrochemical energy storage charging sign, wherein a charging time value is 1, and a non-charging time value is 0; p (P) L,i The system load is the moment i; p (P) tie,i The power is transmitted in a power saving way for the moment i, so that the outflow is positive; p (P) p,i 、P s,i Respectively pumping the real-time power of the energy storage unit and the all-vanadium redox flow battery at the moment i;
Thermal power generating unit output constraint considering flexibility:
wherein: p (P) j,max The upper limit of the output of the conventional thermal power generating unit j; p (P) j,min The method is a lower output limit before flexible modification of a conventional thermal power generating unit j.
The specific process of the step 4 is as follows:
step 4.1, inputting the load and the real historical operation data of wind power generation into a double-layer planning model, predicting a typical scene data time sequence, and drawing a typical scene data time sequence power curve;
step 4.2, determining the maximum payload according to a typical scene data time sequence power curve, giving a thermal power flexibility modified installation initial value according to the maximum payload, and setting the installation initial value as the lower limit of the thermal power unit; inputting a typical scene data time sequence power curve into an upper-layer economy model objective function, configuring hybrid energy storage on the basis of a given thermal power unit, and performing time sequence simulation to obtain thermal power units, hybrid energy storage configuration, wind abandoning, coal burning cost and working time sequences of the thermal power units and energy storage; generating an initial mixed energy storage and thermal power unit distributed group, and taking the initial mixed energy storage and thermal power unit distributed group as input of a lower-layer flexibility model objective function;
step 4.3, solving a Pareto optimal solution set by using an NSGA-III algorithm according to constraint conditions and with the lowest objective function flexibility penalty cost and the maximum carbon yield of the lower-layer flexibility model, and judging whether the hybrid energy storage and thermal power generating unit flexibility transformation coordination planning corresponding to the optimal solution is an optimal scheme or not;
Step 4.4, if not, returning to an upper economic model to update population speed and position, namely correcting the hybrid energy storage capacity and the thermal power unit flexibility transformation capacity feasible region to generate a new hybrid energy storage and thermal power unit flexibility transformation allocation group; if yes, outputting a hybrid energy storage and thermal power generating unit flexibility transformation coordination planning scheme corresponding to the optimal solution.
The invention has the beneficial effects that:
according to the thermal power unit flexibility transformation and hybrid energy storage coordinated planning method, the thermal power unit flexibility transformation and hybrid energy storage double-layer planning model with flexibility is designed, carbon emission constraint is considered, and better economic and environmental benefits are achieved; the energy storage technology is not limited in type, the economy and flexibility of each energy storage scheme can be compared from multiple angles, and the method is convenient, effective and easy to realize. The economic optimal solution is sought on the basis of meeting a series of conditions such as reliability technical indexes, environmental protection benefit indexes and the like, and better economic benefit can be brought.
Drawings
FIG. 1 is a schematic diagram of a conventional unit with insufficient peak shaving and wind curtailment;
FIG. 2 is a schematic diagram of a power transmission blocking wind curtailment;
FIG. 3 is a diagram showing the change of the annual payload timing sequence of the system before and after the new energy is accessed;
FIG. 4 is a thermal power flexibility transformation and hybrid energy storage capacity double-layer planning model in the invention;
FIG. 5 is a flow chart of a solution of a two-layer planning model in the present invention;
FIG. 6 is a schematic diagram of installed capacity of newly added resources in different planning years;
FIG. 7 is a graph showing the comparison of the newly installed capacity of each resource and the new energy consumption cost;
FIG. 8 is a schematic diagram of typical daily up-regulation flexibility adjustment capabilities for different scenarios;
FIG. 9 is a schematic diagram of typical day downregulation flexibility adjustment capabilities for different scenarios;
FIG. 10 is a schematic diagram of newly added capacity and carbon emissions benefits under different carbon emissions constraints;
FIG. 11 is Y 0 A schematic of the relationship between +3 year flexible resource capacity and corresponding costs.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and detailed description.
Example 1
The invention relates to a hybrid energy storage joint planning method considering the flexible supply-demand balance of an electric power system, which is implemented according to the following steps:
as shown in fig. 1 and fig. 2, after wind power with strong volatility and anti-peak shaving characteristics is connected to a power grid in a large scale, as a conventional thermal power generating unit is difficult to quickly respond to wind power output fluctuation, the system is beyond the capacity of receiving wind power, peak shaving deficiency wind discarding is generated, and the wind discarding expression is as follows:
Wherein: p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) W (t) is the wind power at time t; p (P) FR (t) is the wind power acceptable by the system at the moment t;
the expression of the wind curtailment due to the power transmission line conveyance blockage is:
wherein: p (P) LT (t) delivering blocking wind-abandoning power at t time; p (P) LM Maximum power transmission capacity for the power transmission line; p (P) W (t) is the wind power at time t;
the conventional unit peak regulation insufficient waste wind and conveying blockage waste wind under the same time sequence obtained by the calculation formula (1) and the calculation formula (2) are calculated to obtain total waste wind, wherein the calculation formula is as follows:
P L (t)＝max{P LG (t),P LT (t)} (3)
wherein: p (P) L (t) is the total wind curtailed power at time t; p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) LT And (t) delivering blocking wind-discarding power at t time.
The system flexibility requirement is defined as the system adjustment capability required by the change of the net load uncertainty, and the system flexibility requirement is combined with the thermal power unit flexibility transformation, pumped storage and all-vanadium redox flow battery flexibility supply capability, and the specific process is as follows:
step 2.1, flexibility demand analysis:
as shown in fig. 3, when the new energy access ratio is high, the amplitude and frequency of the annual payload timing curve of the system change greatly, which causes running safety or electricity limitation problems due to insufficient system flexibility adjustment space. The new energy and the load are typical consumption main bodies of flexible resources, and under the common influence of the double variables of new energy power generation and load uncontrollable power, the system flexibility demand is rapidly increased, and the power grid is required to have higher flexibility supply capacity.
Demand for System flexibility F n,t Defined as coping with payload P J Varying the tuning capabilities that flexible resources within the system can provide:
F n,t ＝P J,t+1 -P J,t (4)
wherein F is n,t The flexibility requirement of the system at the moment t; p (P) J,t And P J,t+1 The net loads at the time t and the time t+1 of the system are respectively represented;
P J,t ＝P Load,t -P RE,t (5)
wherein P is RE,t For the power of new energy sources such as wind at t moment, P Load,t The load at the moment t; p (P) J,t Representing the net load at time t of the system;
by the formulas (4) and (5), the uncertainty of the source load is quantized into the flexibility adjustment capability required by the power system in a certain time scale, and then the system flexibility requirement at the moment t is as follows:
in the method, in the process of the invention,and->The system up-regulation flexibility requirement and the down-regulation flexibility requirement at the moment t are respectively;
step 2.2, the flexibility transformation supply capacity expression of the thermal power generating unit is as follows:
in the method, in the process of the invention,and->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation; p (P) j,max The maximum output before the thermal power unit is flexibly modified; p (P) j*,min Respectively the minimum output after the thermal power unit is flexibly modified; />Modifying the downward climbing rate of the thermal power unit g for flexibility; />Modifying the upward climbing speed of the thermal power unit g for flexibility; τ is the time scale;
pumped storage is an energy storage device with the characteristics of large capacity, large period and the like. The scale of the flexible resources it provides is measured by the following formula:
In the method, in the process of the invention,the upward and downward flexibility adjusting capability of the pumped storage is respectively provided; p (P) st,+,max 、P st,-,max Respectively pumping and storing the maximum power generation and the water storage power; s is S t 、S max 、S min The upper limit and the lower limit of the water storage capacity and the water storage capacity at the moment t are respectively; delta is the climbing time interval;
the all-vanadium redox flow battery has the advantages of high response speed, short construction period and no obvious aging mechanism because the power and the capacity can be independently designed, and can realize more durable and more stable charge and discharge compared with flywheel energy storage, super capacitor and the like; compared with a lithium battery, the lithium battery has low price, is safe and reliable, and is one of the best energy storage technologies for inhibiting the fluctuation of new energy power generation. The flexibility supply capability is as follows:
wherein:and->The upward and downward flexibility supply capacity of the all-vanadium redox flow battery is respectively provided;is the actual state of charge of the flow battery; />The maximum charge state and the minimum charge state of the flow battery are respectively; e (E) VRB Is the rated capacity of the flow battery; p (P) + (t) and P- (t) are respectively the charge and discharge power of the flow battery; η (eta) in And eta out The charge and discharge efficiency of the flow battery are respectively; τ is the time scale;
step 2.3, flexibility evaluation index:
through research and analysis, the indexes for measuring the flexibility of the power system mainly comprise: flexibility adjusting capability, climbing power of a unit (upward and downward power generation capability reflects flexibility of the system in different directions), adjusting speed and the like, and the biggest factor limiting renewable energy consumption is the flexibility adjusting capability of the power system.
The power generating rate increasing capability of the unit is upward power generation, and the power generating rate reducing capability is downward power generation; in the same direction, the difference between the flexibility supply and demand in the same time period is defined as the system flexibility margin F MAR,t The expression is:
F MAR,t ＝F S,t -F n,t (11)
wherein F is S,t Represents the flexible provisioning capability that flexible resources within the system can provide;and->Is the up and down flexibility margin that the system can provide; />Upward flexibility adjustment capability provided for renewable energy sources;the ability to adjust the downward flexibility provided for demand response; />Respectively are hybrid energy storageUpward and downward flexibility adjustment capability provided by the system; />Respectively the upward and downward flexibility requirements; />And->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation;the upward and downward flexibility adjusting capability of the pumped storage is respectively provided; />And->Respectively, the upward and downward flexibility supply capacity of the all-vanadium redox flow battery.
Step 3, as shown in fig. 4, a double-layer planning model for flexibility transformation and hybrid energy storage of the thermal power generating unit is established according to the total abandoned wind and the difference value of flexibility supply and demand in the same time period; the double-layer planning model comprises an upper-layer economy model objective function which takes the lowest comprehensive cost as an optimization target, takes the capacity and grid-connected position of hybrid energy storage as decision variables of the model, and further comprises a lower-layer flexibility model objective function which takes the minimum flexibility punishment cost and the maximum carbon income as targets, wherein the decision variables are the output power of flexible resources such as a system power supply unit, hybrid energy storage and the like, and constraint conditions.
The upper layer economic model objective function is:
minC 1 ＝C K +C S +C H +C T -R t (13)
wherein C is 1 The comprehensive cost of the system is realized; c (C) K The comprehensive operation cost of the system comprises punishment cost of demand response and construction and operation maintenance cost of a conventional thermal power generating unit; c (C) T The cost of wind disposal is the cost; p (P) e (t) is the wind-abandoning power absorbed by the energy storage at the moment t; mu (mu) T The wind power penalty value is discarded per unit; t (T) S Planning a period; c (C) H 、C s The investment cost and the operation and maintenance cost of the pumped storage and all-vanadium redox flow battery are respectively; r is R t Generating benefits for the thermal power generating unit;
the pumped storage cost comprises the construction cost of the newly added pumped storage unit and the operation and maintenance cost of the pumped storage unit, and is expressed as:
C H ＝P H K H +E H k H /n H (14)
wherein C is H The new construction cost and the operation and maintenance cost are used for pumped storage; p (P) H 、k H The capacity of the total assembly machine of the pumped storage unit and the operation and maintenance cost coefficient thereof are respectively; e (E) H The new pumping energy storage capacity is built; k (k) H The construction cost coefficient of pumped storage; n is n H The operation life of the pump is stored;
assuming that all the vanadium redox flow batteries are newly built, the cost comprises investment cost and operation and maintenance cost, the investment cost main body of the all the vanadium redox flow batteries is the battery cost, and the cost C of the all the vanadium redox flow batteries is calculated according to the rated capacity s Expressed as:
C s ＝E es k es (m s /n s +ν) (15)
wherein C is S Is the total cost of the all-vanadium redox flow battery; e (E) es The capacity of the vanadium redox flow battery is newly increased; k (k) es The construction cost coefficient of the vanadium redox flow battery is the construction cost coefficient of the vanadium redox flow battery; m is m s 、n s The times of charging and discharging of the all-vanadium redox flow battery and the total times of chargeable and dischargeable times in the whole life cycle are respectively; v is the operation and maintenance cost coefficient of the all-vanadium redox flow battery;
the generating income of the thermal power generating unit comprises the network electric quantity income of the power grid company for the thermal power generating unit and the operation compensation cost of the power grid for the thermal power generating unit participating in the flexibility improvement, and the concrete expression is as follows:
/>
wherein R is t Generating benefits for the thermal power generating unit;F G the method comprises the steps of respectively compensating the network-surfing electric quantity income of the thermal power generating unit and the operation compensation cost of the thermal power generating unit; w (W) G,i The method comprises the steps of surfing the internet for the ith unit; c (C) fit The method is characterized in that the internet electricity price of thermal power generation is achieved; p (P) G,i (t) is the power of the ith unit at the moment t; c (C) pr,GP The compensation unit price is modified for the flexibility of the thermal power generating unit; t is t 1 The time period is modified for the flexibility of the thermal power generating unit; p (P) a,i The minimum output of the conventional peak shaving stage of the ith unit is obtained;
the underlying flexible model objective function is as follows:
wherein C is MAR Penalty costs for inflexibility; beta down 、β up Respectively representing downward and upward flexibility deficiency punishment coefficients;and->Is the up and down flexibility margin that the system can provide; a, a c A fee for the carbon trade; b (B) c Is carbon yield; e, e c CO produced by combustion of coal of unit mass 2 Is a conversion coefficient of (a); e (E) RE,t Generating energy for new energy; θ c Coal consumption for producing unit electric energy;
the formula of the thermal power generating unit flexibility transformation cost is as follows:
C F ＝O g (P a -P j*,min ) (20)
wherein C is F The cost is improved for the flexibility of the thermal power generating unit;the lower limit of the output after the flexibility modification of the thermal power unit j is set; o (O) g The unit cost for the flexible reconstruction of the thermal power generating unit is realized; p (P) a The lower limit of the output before the thermal power unit is flexibly modified.
The constraint conditions are specifically as follows:
electric quantity balance constraint:
W g +W w -ΔW w ≥W L (21)
in which W is g 、W w 、ΔW w 、W L The method comprises the steps of generating capacity, wind power generating capacity, wind discarding capacity and load capacity of the thermal power generating unit respectively;
pumped storage reservoir capacity constraint and daily clearance constraint:
wherein E is H,i Drawing the water storage capacity of the power storage station at the moment i; e (E) H,min 、E H,max Sequentially minimum water storage capacity of upper reservoir of pumping and storing power stationAnd the maximum water storage capacity; η (eta) pump 、η gen Pumping water and generating power respectively; t (T) S Is a unit time; mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0; p (P) p,i Real-time power of the pump storage unit at the moment i;
output constraint of pumped storage unit
/>
E eH ＝α H P H (25)
Wherein alpha is H Pumping/storing time from dead water level to full water level or from full water level to dead water level for the pumped storage unit under rated power; e (E) eH Rated water storage capacity of the upper reservoir is pumped and stored; p (P) p,i Real-time power of the pump storage unit at the moment i; e (E) H,min 、E H,max Sequentially the minimum water storage capacity and the maximum water storage capacity of the upper reservoir of the pumping and storage power station;
all-vanadium redox flow battery power constraint:
in the method, in the process of the invention,respectively the minimum value and the maximum value of the power of the all-vanadium redox flow battery, P e,t The power at the moment t of the vanadium redox flow battery; />And->E is the minimum value and the maximum value of the capacity of the all-vanadium redox flow battery e,t Is the capacity of the vanadium redox flow battery in a time period t;
carbon emission constraint:
in the method, in the process of the invention,maximum carbon emission for the t-th year; mu (mu) g Is the carbon emission rate; e (E) g,t Generating energy for a thermal power generating unit of the t year;
flexible supply and demand balance constraint:
F S,t +F FG,t +F N,t +|F MAR,t |≥|F n,t | (29)
wherein F is S,t 、F FG,t And F N,t Flexibility supply capability for the hybrid energy storage system, the thermal power flexibility transformation and the demand response respectively; f (F) MAR,t A margin of system flexibility; f (F) n,t Is a system flexibility requirement;
system power balance constraint:
wherein: mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0;is a variable of 0-1 and satisfies +.> The method comprises the steps of (1) marking an electrochemical energy storage charging sign, wherein a charging time value is 1, and a non-charging time value is 0; p (P) L,i The system load is the moment i; p (P) tie,i The power is transmitted in a power saving way for the moment i, so that the outflow is positive; p (P) p,i 、P s,i Respectively pumping the real-time power of the energy storage unit and the all-vanadium redox flow battery at the moment i;
thermal power generating unit output constraint considering flexibility:
wherein: p (P) j,max The upper limit of the output of the conventional thermal power generating unit j; p (P) j,min The method is a lower output limit before flexible modification of a conventional thermal power generating unit j.
And 4, preprocessing data by adopting a sequencing method according to a model solving flow chart shown in fig. 5, and determining the input sequence of the flexible resources. Normalizing the variable to be optimized by adopting an entropy weight method, and calculating the information entropy e of the variable to be optimized j Utility value d j Entropy weight omega j The method comprises the steps of carrying out a first treatment on the surface of the Then, an optimal scheme is determined by adopting an approach ideal solution ordering method, and a comprehensive weighting index is calculated and matrix normalization is carried out. The optimal input sequence of each flexible resource can be obtained by adopting an entropy weight method and an approximate ideal solution ordering method, wherein the optimal input sequence is as follows: pumped storage, flexibility transformation of a thermal power unit and all-vanadium redox flow battery. The specific process is as follows:
inputting the load and the real historical operation data of wind power generation into a double-layer planning model, predicting a typical scene data time sequence, and drawing a typical scene data time sequence power curve; determining the maximum payload according to a typical scene data time sequence power curve, giving an initial value of the installation after the thermal power flexibility is improved according to the maximum payload, and setting the initial value as the lower limit of the thermal power assembly installation; inputting a typical scene data time sequence power curve into an upper-layer economy model objective function, configuring hybrid energy storage on the basis of a given thermal power unit, and performing time sequence simulation to obtain thermal power units, hybrid energy storage configuration, wind abandoning, coal burning cost and working time sequences of the thermal power units and energy storage; generating an initial mixed energy storage and thermal power unit distributed group, and taking the initial mixed energy storage and thermal power unit distributed group as input of a lower-layer flexibility model objective function; solving a Pareto optimal solution set by using a NSGA-III algorithm according to the target of lowest flexibility penalty cost and maximum carbon income of a lower flexibility model target function and combining constraint conditions, and judging whether a hybrid energy storage and thermal power unit flexibility transformation coordination plan corresponding to the optimal solution is an optimal scheme or not; if not, returning to the upper economic model to update the population speed and the position, namely correcting the mixed energy storage capacity and the thermal power unit flexibility transformation capacity feasible region to generate a new mixed energy storage and thermal power unit flexibility transformation allocation group; if yes, outputting a hybrid energy storage and thermal power generating unit flexibility transformation coordination planning scheme corresponding to the optimal solution.
The invention provides a hybrid energy storage joint planning method considering the flexible supply-demand balance of a power system, comprehensively considers the flexible transformation and hybrid energy storage coordination planning of a thermal power unit, takes the capacity and grid-connected position of hybrid energy storage as decision variables of the model, comprehensively considers the economy and flexibility of a power grid, and provides a thermal power unit flexible transformation and hybrid energy storage double-layer planning model considering the flexibility. Aiming at the problem of insufficient flexibility transformation capability of the thermal power unit, from the perspective of collaborative planning of three types of flexibility resources, namely the flexibility transformation of the thermal power unit, the all-vanadium redox flow battery and the pumped storage, the planning economy and the operation flexibility of the system can be effectively improved.
Example 2
The actual measured annual load and annual wind power output data of a certain area of Meng Dong are used for carrying out calculation analysis, the electric installation scale of the calculation is 950MW, the planning period is determined to be 5 years, and the maximum load increasing trend of the planning year is shown in Table 3. The minimum output before and after the flexible transformation of the thermal power unit is 0.6,0.3 of rated capacity respectively; the punishment cost of the upward and downward flexibility deficiency is respectively 0.0517 and 0.129 ten thousand yuan/MW, the maximum installed capacity of the pumped storage in the area is 1200MW in the future, when the pumped storage unit operates at rated power, the pumping/storage time=8h from the dead water level to the full water level (or from the full water level to the dead water level) of the lower upper reservoir, the calculation basic parameters are shown in table 1, the peak-valley electricity price is shown in table 2, and the maximum planned year load is shown in table 3.
TABLE 1
TABLE 2
TABLE 3 Table 3
(1) Planning results and analysis
In Y form 0 As reference year, simulate to obtain Y 0 +1、Y 0 +3、Y 0 The installed situation for the +5 programming year and the costs are shown in tables 4 and 6.
TABLE 4 Table 4
As can be seen from Table 4 and FIG. 6, at the initial stage of planning Y 0 In +1 year, the increase of the electric power and electricity quantity requirements is less, however, the flexibility of the thermal power unit is selected to reform 1500MW without newly creating a conventional thermal power unit due to the low operation and maintenance cost and the low construction cost of the new energy unit. This indicates that the flexible resource can improve the system economy while improving the system flexibility adjustment capability. During planning period Y 0 +3、Y 0 In +5 years, due to the rapid increase of the electric power and electricity demand of the system and the requirement of high-proportion new energy grid connection, the installation scale of wind power generation is greatly increased, the installation proportion of wind power is increased by 23.4%, the installation proportion of thermal power is reduced from 73.5% to 50.1%, which means that the energy supply ratio of new energy in a future new energy high-permeability system can be gradually increased, but the initial construction cost of the new energy is higher, so the operation and maintenance cost, fuel and ring of the system are higherThe environmental cost is greatly increased. Therefore, aiming at the current situation that the flexibility adjustment capability is insufficient due to the randomness of large-scale new energy, the planning economy and the operation flexibility of the thermal power generating unit can be effectively improved by introducing flexible resources such as hybrid energy storage, demand response and the like on the basis of the flexibility adjustment capability.
(2) Different scene comparison analysis
The planning capacity and the flexible resource compensation cost of different scenes are shown in table 5, and the new installation capacity and the new energy consumption cost of each resource are shown in fig. 7 by adopting Y 0 And (4) setting three scenes according to +1 year data, and respectively comparing the influences of different access flexible resource types in the same planning period on the planning result.
Scene one: only the flexibility transformation of the thermal power generating unit is considered.
Scene II: consider thermal power unit flexibility transformation and pumped storage.
Scene III: consider thermal power unit flexibility transformation and hybrid energy storage.
TABLE 5
As can be seen from table 5 and fig. 7, in the newly added wind installation 1600MW of the scene one, because only the flexibility transformation of the thermal power unit is considered, the flexibility adjustment capability of the high-permeability new energy system is insufficient, the wind rejection rate is 11.43%, and meanwhile, under the condition that the new energy is permeated in a high proportion, the flexibility requirement of the system is difficult to meet due to the fact that the flexibility transformation of the thermal power unit is independently relied on, and therefore, different types of flexible resources such as hybrid energy storage and the like are required to be input for coordinated optimization. 1200MW of a wind installation machine is newly added in a second scene, 1800MW of a thermal power unit is selectively and flexibly transformed to provide flexibility adjusting capability for the system, meanwhile, 1068MW pumped storage units are configured, and the wind rejection rate is reduced by 4.85%. The scene III comprehensively considers the flexibility transformation and the hybrid energy storage optimal configuration of the thermal power generating unit, the wind abandoning rate is only 2.87 percent, and compared with the scene I and the scene II with less flexible resources, the provided flexibility adjusting capacity is greatly increased, and the novel energy consumption is facilitated.
(3) Typical day flexibility analysis
Selecting Y 0 The typical daily static load time sequence characteristic curve with the maximum peak-valley difference of +5 years is compared and analyzed according to the three scenes, the flexibility of the typical daily operation is analyzed, and the flexibility deficiency penalty cost of different scenes is shown in table 6:
TABLE 6
As can be seen from fig. 8 and 9, respectively, the flexibility adjustment capability provided by scene three under three scenes is the highest. As shown in fig. 8, the up-regulation flexibility capacity provided by scene one is about 1000MW lower than that provided by scene three at the same time, which would create a risk of load shedding. As shown in fig. 9, as the scene three comprehensively considers the thermal power unit flexibility transformation and the hybrid energy storage joint planning, the down-regulation flexibility capability of the system is effectively improved, and the new energy utilization rate is improved.
As can be seen from the overall analysis of the table 6, the fig. 8 and the fig. 9, the flexibility requirement is greatly increased due to the high-proportion permeation of the new energy, the flexibility supply and demand balance characteristic is considered in the first scene, but only the flexibility modification of the thermal power unit is considered to provide certain flexibility, so that the flexibility adjustment capability of the system is insufficient, a large amount of abandoned wind is generated, and the flexibility punishment cost is highest. Scene two considers thermal power generating unit flexibility transformation and pumped storage coordination configuration, and compared with scene one, the up and down adjustment flexibility capacity of scene two is improved to some extent, but still can not satisfy the flexibility demand of system. And the thermal power unit flexibility transformation and hybrid energy storage coordination optimization are comprehensively considered in a third scene, the flexibility of the system is insufficient, the punishment cost is minimum, the flexibility adjustment capability of the system is effectively improved, and the new energy consumption capability is improved.
(4) Considering the influence of different carbon emission limits on the planning result
As shown in fig. 10, the upper limit of the carbon emission amount is set to 100%, 40% and 20% of the reference annual carbon emission amount, respectively, and Y is selected 0 +3 is the reference year, three different carbon emission limits are obtainedThe carbon yield and the new installed capacity of each system resource are increased.
As can be seen from fig. 10, the introduction of carbon trade benefits allows for a reasonable optimization of the energy structure of the power system. When the carbon emission upper limit is reduced in the order of 100%, 40% and 20% of the reference annual carbon emission, the newly installed capacity of the thermal power generating unit gradually decreases to 0. In order to meet the requirements of high randomness and high volatility of new energy power generation such as large-scale wind power and the like on system flexibility, the investment scale of flexible resources is continuously enlarged. The carbon trade income shows a trend of rising and then falling along with the reduction of the limit value of the carbon emission, and the construction scale of the hybrid energy storage system with small early investment is increased along with the reduction of the carbon emission and reaches the optimal capacity due to the influences of factors such as the flexibility transformation capacity, the demand response and the like of the thermal power generating unit.
(5) Influence of different flexible resource capacities on planning costs
As can be seen from fig. 11, the overall cost of the system shows a trend of increasing and then decreasing, and the net benefit of the flexible resource (the difference between the investment cost and the adjustment compensation cost) increases with the increase of the allocation capacity of the flexible resource. On the premise of meeting the system flexibility requirement, when the system configures 5000MW flexible resource capacity, the net gain growth speed of the system flexible resource is the fastest, and the comprehensive cost of the system is the smallest.

Claims (8)

1. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the power system is characterized by being implemented according to the following steps:
step 1, calculating total abandoned wind according to time sequence coupling characteristics of abandoned wind and power transmission blocking abandoned wind generated by insufficient peak shaving of a conventional unit under the same time sequence;
step 2, defining the system flexibility requirement as the system adjustment capability required by dealing with the change of the net load uncertainty, and calculating the difference between the flexibility supply and the requirement in the same time period by combining the flexibility transformation of the thermal power unit, the pumped storage and the flexibility supply capability of the vanadium redox flow battery;
step 3, establishing a thermal power unit flexibility transformation and hybrid energy storage double-layer planning model considering flexibility by combining total abandoned wind and the difference value of flexibility supply and demand in the same time period;
and 4, solving a double-layer planning model by adopting an NSGA-III algorithm to obtain a thermal power unit flexibility transformation and hybrid energy storage configuration scheme.
2. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the electric power system according to claim 1, wherein the specific process of step 1 is as follows:
after wind power with strong fluctuation and anti-peak shaving characteristics is connected into a power grid in a large scale, as the conventional thermal power generating unit is difficult to quickly respond to wind power output fluctuation, the capacity of the system for receiving wind power is exceeded, peak shaving deficiency wind discarding is generated, and the wind discarding expression is as follows:
Wherein: p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) W (t) is the wind power at time t; p (P) FR (t) is the wind power acceptable by the system at the moment t;
the expression of the wind curtailment due to the power transmission line conveyance blockage is:
wherein: p (P) LT (t) delivering blocking wind-abandoning power at t time; p (P) LM Maximum power transmission capacity for the power transmission line; p (P) W (t) is the wind power at time t;
the conventional unit peak regulation insufficient waste wind and conveying blockage waste wind under the same time sequence obtained by the calculation formula (1) and the calculation formula (2) are calculated to obtain total waste wind, wherein the calculation formula is as follows:
P L (t)＝max{P LG (t),P LT (t)} (3)
wherein: p (P) L (t) is the total wind curtailed power at time t; p (P) LG (t) is the abandoned wind power generated by insufficient peak regulation of the conventional unit at the moment t; p (P) LT And (t) delivering blocking wind-discarding power at t time.
3. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the power system according to claim 3, wherein the specific process of the step 2 is as follows:
step 2.1, system flexibility requirement F n,t Defined as coping with payload P J Varying the tuning capabilities that flexible resources within the system can provide:
F n,t ＝P J,t+1 -P J,t (4)
wherein F is n,t The flexibility requirement of the system at the moment t; p (P) J,t And P J,t+1 The net loads at the time t and the time t+1 of the system are respectively represented;
P J,t ＝P Load,t -P RE,t (5)
Wherein P is RE,t For the power of new energy sources such as wind at t moment, P Load,t The load at the moment t; p (P) J,t Representing the net load at time t of the system;
by the formulas (4) and (5), the uncertainty of the source load is quantized into the flexibility adjustment capability required by the power system in a certain time scale, and then the system flexibility requirement at the moment t is as follows:
in the method, in the process of the invention,and->The system up-regulation flexibility requirement and the down-regulation flexibility requirement at the moment t are respectively;
step 2.2, the flexibility transformation supply capacity expression of the thermal power generating unit is as follows:
in the method, in the process of the invention,and->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation; p (P) j,max The maximum output before the thermal power unit is flexibly modified; p (P) j*,min Respectively the minimum output after the thermal power unit is flexibly modified;modifying the downward climbing rate of the thermal power unit g for flexibility; />Modifying the upward climbing speed of the thermal power unit g for flexibility; τ is the time scale;
the flexibility of pumped storage is given by the following expression:
in the method, in the process of the invention,the upward and downward flexibility adjusting capability of the pumped storage is respectively provided; p (P) st,+,max 、P st,-,max Respectively pumping and storing the maximum power generation and the water storage power; s is S t 、S max 、S min The upper limit and the lower limit of the water storage capacity and the water storage capacity at the moment t are respectively; delta is the climbing time interval;
the flexible supply capacity expression of the vanadium liquid flow is as follows:
Wherein:and->The upward and downward flexibility supply capacity of the all-vanadium redox flow battery is respectively provided; />Is the actual state of charge of the flow battery; />The maximum charge state and the minimum charge state of the flow battery are respectively; e (E) VRB Is the rated capacity of the flow battery; p (P) + (t) and P- (t) are respectively the charge and discharge power of the flow battery; η (eta) in And eta out The charge and discharge efficiency of the flow battery are respectively; τ is the time scale;
step 2.3, the capability of the unit for increasing the power generation rate is upward power generation, and the capability for reducing the power generation rate is downward power generation; in the same direction, the difference between the flexibility supply and demand in the same time period is defined as the system flexibility margin F MAR,t The expression is:
F MAR,t ＝F S,t -F n,t (11)
wherein F is S,t Represents the flexible provisioning capability that flexible resources within the system can provide;and->Is the up and down flexibility margin that the system can provide; />Upward flexibility adjustment capability provided for renewable energy sources;the ability to adjust the downward flexibility provided for demand response; />The upward and downward flexibility adjustment capability provided by the hybrid energy storage system, respectively; />Respectively the upward and downward flexibility requirements;and->The flexibility supply capability of the thermal power unit is respectively upward and downward after the flexibility transformation; The upward and downward flexibility adjusting capability of the pumped storage is respectively provided; />And->Respectively, the upward and downward flexibility supply capacity of the all-vanadium redox flow battery.
4. The hybrid energy storage joint planning method considering the flexible supply and demand balance of the electric power system according to claim 1, wherein the dual-layer planning model in the step 3 comprises an upper-layer economic model objective function taking the lowest comprehensive cost as an optimization target, taking the capacity and grid-connected position of the hybrid energy storage as decision variables of the model, and further comprises a lower-layer flexible model objective function taking the minimum flexibility penalty cost and the maximum carbon benefit as targets, wherein the decision variables are the output power of flexible resources such as a system power supply unit, the hybrid energy storage and the like, and constraint conditions.
5. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the electric power system according to claim 4, wherein the upper-layer economic model objective function is:
minC 1 ＝C K +C S +C H +C T -R t (13)
wherein C is 1 The comprehensive cost of the system is realized; c (C) K The comprehensive operation cost of the system comprises punishment cost of demand response and construction and operation maintenance cost of a conventional thermal power generating unit; c (C) T The cost of wind disposal is the cost; p (P) e (t) is the wind-abandoning power absorbed by the energy storage at the moment t; mu (mu) T The wind power penalty value is discarded per unit; t (T) S Planning a period; c (C) H 、C s The investment cost and the operation and maintenance cost of the pumped storage and all-vanadium redox flow battery are respectively; r is R t Generating benefits for the thermal power generating unit;
the pumped storage cost comprises the construction cost of the newly added pumped storage unit and the operation and maintenance cost of the pumped storage unit, and is expressed as:
C H ＝P H K H +E H k H /n H (14)
wherein C is H The new construction cost and the operation and maintenance cost are used for pumped storage; p (P) H 、k H The capacity of the total assembly machine of the pumped storage unit and the operation and maintenance cost coefficient thereof are respectively; e (E) H The new pumping energy storage capacity is built; k (k) H The construction cost coefficient of pumped storage; n is n H The operation life of the pump is stored;
assuming that all the vanadium redox flow batteries are newly built, the cost comprises investment cost and operation and maintenance cost, the investment cost main body of the all the vanadium redox flow batteries is the battery cost, and the cost C of the all the vanadium redox flow batteries is calculated according to the rated capacity s Expressed as:
C s ＝E es k es (m s /n s +ν) (15)
wherein C is S Is the total cost of the all-vanadium redox flow battery; e (E) es The capacity of the vanadium redox flow battery is newly increased; k (k) es The construction cost coefficient of the vanadium redox flow battery is the construction cost coefficient of the vanadium redox flow battery; m is m s 、n s The times of charging and discharging of the all-vanadium redox flow battery and the total times of chargeable and dischargeable times in the whole life cycle are respectively; v is the operation and maintenance cost coefficient of the all-vanadium redox flow battery;
the generating income of the thermal power generating unit comprises the network electric quantity income of the power grid company for the thermal power generating unit and the operation compensation cost of the power grid for the thermal power generating unit participating in the flexibility improvement, and the concrete expression is as follows:
Wherein R is t Generating benefits for the thermal power generating unit;F G the method comprises the steps of respectively compensating the network-surfing electric quantity income of the thermal power generating unit and the operation compensation cost of the thermal power generating unit; w (W) G,i The method comprises the steps of surfing the internet for the ith unit; c (C) fit The method is characterized in that the internet electricity price of thermal power generation is achieved; p (P) G,i (t) is the power of the ith unit at the moment t; c (C) pr,GP The compensation unit price is modified for the flexibility of the thermal power generating unit; t is t 1 The time period is modified for the flexibility of the thermal power generating unit; p (P) a,i The minimum output of the conventional peak shaving stage of the ith unit is obtained.
6. The hybrid energy storage joint planning method considering power system flexible supply-demand balance according to claim 5, wherein the lower layer flexible model objective function is as follows:
wherein C is MAR Penalty costs for inflexibility; beta down 、β up Respectively representing downward and upward flexibility deficiency punishment coefficients;and->Is the up and down flexibility margin that the system can provide; a, a c A fee for the carbon trade; b (B) c Is carbon yield; e, e c CO produced by combustion of coal of unit mass 2 Is a conversion coefficient of (a); e (E) RE,t Generating energy for new energy; θ c Coal consumption for producing unit electric energy;
the formula of the thermal power generating unit flexibility transformation cost is as follows:
wherein C is F The cost is improved for the flexibility of the thermal power generating unit;the lower limit of the output after the flexibility modification of the thermal power unit j is set; o (O) g The unit cost for the flexible reconstruction of the thermal power generating unit is realized; p (P) a The lower limit of the output before the thermal power unit is flexibly modified.
7. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the electric power system according to claim 6, wherein the constraint condition is specifically:
electric quantity balance constraint:
W g +W w -ΔW w ≥W L (21)
in which W is g 、W w 、ΔW w 、W L The method comprises the steps of generating capacity, wind power generating capacity, wind discarding capacity and load capacity of the thermal power generating unit respectively;
pumped storage reservoir capacity constraint and daily clearance constraint:
wherein E is H,i Drawing the water storage capacity of the power storage station at the moment i; e (E) H,min 、E H,max Sequentially the minimum water storage capacity and the maximum water storage capacity of the upper reservoir of the pumping and storage power station; η (eta) pump 、η gen Pumping water and generating power respectively; t (T) S Is a unit time; mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0; p (P) p,i Real-time power of the pump storage unit at the moment i;
output constraint of pumped storage unit
E eH ＝α H P H (25)
Wherein alpha is H Pumping/storing time from dead water level to full water level or from full water level to dead water level for the pumped storage unit under rated power; e (E) eH Rated water storage capacity of the upper reservoir is pumped and stored; p (P) p,i Real-time power of the pump storage unit at the moment i; e (E) H,min 、E H,max Sequentially the minimum water storage capacity and the maximum water storage capacity of the upper reservoir of the pumping and storage power station;
All-vanadium redox flow battery power constraint:
in the method, in the process of the invention,respectively the minimum value and the maximum value of the power of the all-vanadium redox flow battery, P e,t The power at the moment t of the vanadium redox flow battery; />And->E is the minimum value and the maximum value of the capacity of the all-vanadium redox flow battery e,t Is the capacity of the vanadium redox flow battery in a time period t;
carbon emission constraint:
in θ t C Maximum carbon emission for the t-th year; mu (mu) g Is the carbon emission rate; e (E) g,t Generating energy for a thermal power generating unit of the t year;
flexible supply and demand balance constraint:
F S,t +F FG,t +F N,t +|F MAR,t |≥|F n,t | (29)
wherein F is S,t 、F FG,t And F N,t Flexibility supply capability for the hybrid energy storage system, the thermal power flexibility transformation and the demand response respectively; f (F) MAR,t A margin of system flexibility; f (F) n,t Is a system flexibility requirement;
system power balance constraint:
wherein: mu (mu) pum Is 0-1 variable and satisfies mu pum μ gen ＝0，μ gen The water pumping sign is that the water pumping time value is 1, and the non-water pumping time value is 0;is a variable of 0-1 and satisfies +.>The method comprises the steps of (1) marking an electrochemical energy storage charging sign, wherein a charging time value is 1, and a non-charging time value is 0; p (P) L,i The system load is the moment i; p (P) tie,i The power is transmitted in a power saving way for the moment i, so that the outflow is positive; p (P) p,i 、P s,i Respectively pumping the real-time power of the energy storage unit and the all-vanadium redox flow battery at the moment i;
thermal power generating unit output constraint considering flexibility:
wherein: p (P) j,max The upper limit of the output of the conventional thermal power generating unit j; p (P) j,min Is normalThe lower limit of the output of the fire-rated power unit j before flexible transformation.
8. The hybrid energy storage joint planning method considering the flexible supply-demand balance of the electric power system according to claim 7, wherein the specific process of the step 4 is as follows:
step 4.1, inputting the load and the real historical operation data of wind power generation into a double-layer planning model, predicting a typical scene data time sequence, and drawing a typical scene data time sequence power curve;
step 4.2, determining the maximum payload according to a typical scene data time sequence power curve, giving a thermal power flexibility modified installation initial value according to the maximum payload, and setting the installation initial value as the lower limit of the thermal power unit; inputting a typical scene data time sequence power curve into an upper-layer economy model objective function, configuring hybrid energy storage on the basis of a given thermal power unit, and performing time sequence simulation to obtain thermal power units, hybrid energy storage configuration, wind abandoning, coal burning cost and working time sequences of the thermal power units and energy storage; generating an initial mixed energy storage and thermal power unit distributed group, and taking the initial mixed energy storage and thermal power unit distributed group as input of a lower-layer flexibility model objective function;
step 4.3, solving a Pareto optimal solution set by using an NSGA-III algorithm according to constraint conditions and with the lowest objective function flexibility penalty cost and the maximum carbon yield of the lower-layer flexibility model, and judging whether the hybrid energy storage and thermal power generating unit flexibility transformation coordination planning corresponding to the optimal solution is an optimal scheme or not;
Step 4.4, if not, returning to an upper economic model to update population speed and position, namely correcting the hybrid energy storage capacity and the thermal power unit flexibility transformation capacity feasible region to generate a new hybrid energy storage and thermal power unit flexibility transformation allocation group; if yes, outputting a hybrid energy storage and thermal power generating unit flexibility transformation coordination planning scheme corresponding to the optimal solution.
CN202311404402.3A 2023-10-25 2023-10-25 Hybrid energy storage joint planning method considering flexible supply-demand balance of power system Pending CN117559391A (en)

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