Disclosure of Invention
The invention aims to solve at least one of the technical problems in the prior art and provides a micro-grid time domain rolling optimization scheduling method based on DDR-MPC.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a micro-grid time domain rolling optimization scheduling method based on DDR-MPC comprises the following steps:
step 1, in a day-ahead scheduling stage, a unit and an energy storage battery are considered comprehensively, loads are divided into residential power loads, industrial power loads and commercial power loads, and a day-ahead optimization scheduling model with the lowest day comprehensive operation cost as a target is established for the classified loads on the basis of differentiated price type demand response; wherein, the differentiated price type demand response is marked as DPDR;
step 2, in the in-day scheduling stage, on the basis of a day-ahead optimization scheduling model, combining the differentiated demand response with a model prediction control method, establishing a DDR-MPC-based in-day time domain rolling optimization scheduling model with the aim of minimizing the rolling time domain comprehensive operation cost, and combining the day-ahead optimization scheduling model and the in-day time domain rolling optimization scheduling model to obtain a microgrid time domain rolling optimization scheduling model; the differential demand response is recorded as DDR, and the model prediction control is recorded as MPC;
step 3, solving the micro-grid time domain rolling optimization scheduling model by adopting a time domain rolling composite differential evolution algorithm; wherein, the time domain rolling composite differential evolution is recorded as TDRCDE.
Further, in step 1, an objective function of the day-ahead optimization scheduling model is constructed, where the objective function is:
in the formula:
Τthe total number of time segments of the scheduling period is optimized for one day ahead,
ttaking a positive integer as a time interval;
Gthe number of diesel generator sets;
is composed of
tIn the first period
vThe dispatching cost of the diesel generating set is reduced,
vtaking a positive integer;
is composed of
tTime interval battery scheduling cost;
is composed of
tIn the first period
mDPDR scheduling cost of class load;
is composed of
tWind/light abandon penalty cost per period;
is composed of
tAnd the interaction cost of the microgrid and the external network in the time period.
Further, the mathematical model of each item cost in the objective function of the day-ahead optimization scheduling model is as follows:
wherein, the diesel generating set dispatching cost does:
in the formula:
α v 、
β v 、
λ v is as follows
vA diesel set scheduling cost coefficient;
is as follows
vA diesel generator set is arranged in
tActive power output in time intervals;
and
are respectively the first
vThe unit capacity installation cost, capital recovery factor and maximum output power of the diesel generating set;
and
are respectively the first
vRunning pipe of diesel generating setManaging cost coefficient, annual running hours and capacity factor of the unit;
wherein, the battery scheduling cost is:
in the formula:
the unit capacity installation cost, capital recovery factor and capacity factor of the storage battery respectively;
and
the annual running hours and running management cost coefficients of the storage battery are respectively;
the charging and discharging power of the storage battery in the time period t;
wherein, the DPDR scheduling cost is:
in the formula:
respectively the initial electricity price and the initial electricity consumption of the mth type load in the t period;
respectively indicating the electricity price and the electricity quantity of the mth load after the mth load participates in the DPDR at the time t;
wherein, abandoning wind/abandoning light penalty cost is:
in the formula:
punishing cost for unit air volume abandon;
respectively predicting the output power and the consumption of the wind generating set in the time period t in the day ahead;
punishment cost for unit light quantity abandon;
and
respectively predicting the output power and the consumption of the photovoltaic generator set in the period t in the day ahead;
the interaction cost of the micro-grid and the external grid is as follows:
in the formula:
exchanging power for the micro-grid and the external grid at a time t, wherein electricity purchasing is positive and electricity selling is negative;
trading prices for the amount of electricity for the period t.
Further, in step 1, constraints for constructing a day-ahead optimization scheduling model are included, where the constraints include:
and power balance constraint:
in the formula:
Gthe number of diesel generator sets;
is as follows
vA diesel generator set is arranged in
tThe active power output of the time period is,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is a wind generating set at the day before
tPredicted output power for the time period;
the predicted output power of the photovoltaic generator set in the period t before the day;
for microgrid and external network
tThe power is interacted in time intervals, wherein the electricity purchasing is positive and the electricity selling is negative;
is as follows
mClass load is in
tThe electric quantity after the time interval participates in DPDR;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
the upper and lower limits of the power of the diesel generator set are restricted:
in the formula:
are respectively the first
vMinimum and maximum output power of the diesel generating set;
and (3) climbing restraint of the diesel generator set:
in the formula:
are respectively the first
vThe ascending and descending climbing rates of the diesel generating set;
is a scheduled time difference;
and (3) charge and discharge restraint of the storage battery:
in the formula:
is a storage battery
tA state of charge of the session;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
and
the maximum charging power and the maximum discharging power of the storage battery are respectively;
and
respectively charge effect of accumulatorRate and discharge efficiency;
the energy storage capacity of the storage battery;
and
maximum and minimum states of charge of the battery, respectively;
and (3) interactive power constraint of the microgrid and the external network:
in the formula:
respectively, the minimum and maximum values of the interaction power.
Further, in step 2, the method specifically includes:
step 2.1, establishing a prediction model based on a model prediction control method;
step 2.2, establishing a rolling optimization scheduling model;
and 2.3, introducing a feedback correction link, correcting the output of the micro-grid time domain rolling optimization scheduling model by using an actual measured value, and taking the actual measured value of the micro-grid time domain rolling optimization scheduling model as an initial value of a new round of rolling optimization to form closed-loop optimization control.
Further, the prediction model is:
in the formula:
is a controllable unit
uIn that
tInitial force output value of time period, fromThe result of the open-loop scheduling in the day ahead,
utaking a positive integer as a whole, and taking the integer,
ttaking a positive integer;
is composed of
tTime period prediction future
Time-interval controllable unit
uIncremental output of (d);
is composed of
tTime period prediction future
Time interval controllable unit
uThe output value of (d);
Nto optimize the number of time-domain time segments;
and the climbing power value to be met by the output of each controllable unit in the adjacent prediction time period is obtained.
Further, in step 2.2, an objective function of the rolling optimization scheduling model is constructed, where the objective function is:
in the formula:
is the current time period;
Nto optimize the number of time-domain time segments;
Gthe number of diesel generator sets;
is composed of
tIn the first period
vThe dispatching cost of the diesel generating set is reduced,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is composed of
tTime interval battery scheduling cost;
is composed of
tInteraction cost of the micro-grid and the external network in a time period;
and
are respectively the first day
mClass load is in
tA DPDR scheduling cost and an IDR scheduling cost of a period;
is composed of
tThe air volume is abandoned in a time interval,
,
and
are respectively a wind generating set in the day
tThe output power and actual consumption of the time period;
in order to discard the amount of light in the day,
,
and
are respectively a solar photovoltaic unit
tThe output power and actual consumption of the time period;
punishment cost is given to unit air volume abandonment,
punishment cost for unit light quantity abandon;
the DPDR scheduling cost is as follows:
in the formula:
are respectively the first
mClass load is in
tElectricity price and electricity quantity after the time slot participates in DPDR;
are respectively the first
mClass load is in
tThe electricity price and the load value after the time interval is regulated before the day and then participates in the DPDR;
the IDR scheduling cost is as follows:
in the formula:
is as follows
mClass load is in
tThe actual load reduction of the time interval;
is as follows
mClass I of load
kStep quotation corresponding to the reduction of the grade load;
is as follows
mClass I of load
kStep-reducing load interval;
Kis prepared by reacting with
Corresponding step quote rating.
Further, in step 2.2, constraints for constructing the rolling optimization scheduling model are included, where the constraints are:
power balance constraint
In the formula:
Gthe number of diesel generator sets;
is as follows
vA diesel generator set is arranged in
tThe active power output of the time period is,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is a wind generating set in the sun
tAn output power of the time period;
is a photovoltaic unit in the sun
tAn output power of the time period;
for microgrid and external network
tThe power is interacted in time intervals, wherein the electricity purchasing is positive and the electricity selling is negative;
is as follows
mClass load is in
tThe load value after the time interval is regulated day before and then participates in the DPDR;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
for the user
mIn that
tThe actual load reduction of the time interval;
upper and lower IDR bound
In the formula:
are respectively the first
mThe minimum value and the maximum value of the reduction amount of the class load;
the upper and lower limits of the power of the diesel generator set are restricted:
in the formula:
the minimum output power and the maximum output power of the v-th diesel generator set are respectively;
and (3) climbing restraint of the diesel generator set:
in the formula:
are respectively the first
vThe ascending and descending climbing rates of the diesel generating set;
is a scheduled time difference;
and (3) charge and discharge restraint of the storage battery:
in the formula:
is a storage battery
tTime periodThe state of charge of;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
and
the maximum charging power and the maximum discharging power of the storage battery are respectively;
and
respectively charge efficiency and discharge efficiency of the storage battery;
the energy storage capacity of the storage battery;
and
maximum and minimum states of charge of the battery, respectively;
and (3) interactive power constraint of the microgrid and the external network:
in the formula:
respectively, the minimum and maximum values of the interaction power.
Further, in step 3, a rolling optimization strategy is introduced into a composite differential evolution CDE algorithm to construct a TDRCDE algorithm, wherein the composite differential evolution is recorded as CDE, and specifically, the dynamic optimization process of the TDRCDE algorithm is as follows:
step 3.1, set the population size to
Optimizing the number of time-domain time segments to
NThe maximum number of iterations is
The total time period is
TInitialization of
tTime interval population
Wherein
Representing the th in the population at time t
(ii) individuals;
the total number of the controllable units
UAnd optimizing the number of time-domain time-segments
NBy using
U×
NThe individual elements comprise the output of a diesel generator set, the charge and discharge amount of a storage battery and the load reduction amount;
step 3.2, in the optimization stage
tThe time interval takes the actual output value of each currently known controllable unit as an initial value based on the future
tTo
t+The latest wind and light output prediction data of 4 time periods are used for optimally designing the output force value of each controllable unit of 4 future time periods obtained by day-ahead optimal scheduling
As a reference value;
step 3.3, solving the output force values of all the controllable units in the dispatching time domain in 4 future time periods by adopting a CDE algorithm with the lowest comprehensive operation cost of the micro-grid rolling time domain as a targetOptimal rolling optimization adjustment amount
(ii) a In the CDE operation, the population individuals are sorted according to the principle that the lower the comprehensive operation cost is, the higher the fitness is, the population is divided into a dominant population and a subordinate population according to the division ratio of 1:1, the dominant and subordinate populations are respectively subjected to variation by using two different strategies of random variation and optimal solution variation to give consideration to the convergence speed and the individual diversity, wherein a cross probability factor and a variation scale factor can be respectively set to be 0.85 and 0.5;
step 3.4, carrying out merging recombination on the good and bad clusters to obtain new clusters, and continuing iteration on the clusters
g=
g+1, if
g<
When the condition is satisfied, the step returns to the step 3.3
g=
Then, optimizing to obtain optimal population
Outputting the optimal value of the current iteration population
(ii) a And will predict the future made by model scheduling
4Sequence of optimal force output values of each controllable unit in each time period
For updating the sequence of optimally planned force values for each controllable unit
;
Step 3.5, dispatching time domain to continue advancing
t=
t+1 if the condition is satisfied
t=
TWhen the optimal value is obtained, the sorting of the optimized and combined population is stopped; if the condition is not satisfied, go to step 3.1, whereOptimal population for a rolling optimization process
To construct an initialization population
And then, obtaining a new generation of population through the variation crossover operation of differential evolution, and repeating the steps until the conditions are met to obtain the optimal value of the comprehensive operation cost of the micro-grid rolling time domain.
As can be seen from the above description of the present invention, compared with the prior art, the microgrid time domain rolling optimization scheduling method based on differential demand response model predictive control according to the present invention at least includes one of the following beneficial effects:
1. due to the combination of the DDR method and the MPC method, the comprehensive operation cost of MPC-based microgrid rolling optimization scheduling can be remarkably reduced, and the wind and light absorption capability of a microgrid system is improved;
2. by providing a micro-grid multi-time scale scheduling strategy based on a DPDR-intra-day DDR-MPC considering demand response timeliness and difference, demand response resources can be fully utilized, output fluctuation of distributed power supplies of the micro-grid is reduced, scheduling errors caused by wind and light prediction errors are reduced, and reliability of optimal scheduling of the micro-grid is improved;
3. the proposed time domain rolling composite differential evolution algorithm can efficiently solve the model, can remarkably improve the optimizing convergence speed and has good dynamic environment adaptability;
4. when the microgrid is in an island operation mode, due to the fact that the microgrid lacks power support provided by an external network and is influenced by self capacity limit and uncertainty of output of renewable energy sources, the reliability of optimized scheduling is relatively poor, and the method provided by the invention can effectively improve the reliability of optimized scheduling of the island microgrid.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.
Referring to fig. 1 to 3, in a preferred embodiment of the present invention, a method for scheduling micro-grid time domain rolling optimization based on DDR-MPC includes the following steps:
step 1, in a day-ahead scheduling stage, a unit and an energy storage battery are considered comprehensively, loads are divided into residential power loads, industrial power loads and commercial power loads, and a day-ahead optimization scheduling model with the lowest day comprehensive operation cost as a target is established for the classified loads on the basis of differentiated price type demand response; wherein, Differential Price Demand Response (DPDR) is recorded as DPDR;
step 2, in the in-day scheduling stage, on the basis of a day-ahead optimization scheduling model, combining the differentiated demand response with a model prediction control method, establishing a DDR-MPC-based in-day time domain rolling optimization scheduling model with the aim of minimizing the rolling time domain comprehensive operation cost, and combining the day-ahead optimization scheduling model and the in-day time domain rolling optimization scheduling model to obtain a microgrid time domain rolling optimization scheduling model; wherein, differential demand response (differentiated demand response) is recorded as DDR, and model predictive control (model predictive control) is recorded as MPC;
step 3, solving the micro-grid time domain rolling optimization scheduling model by adopting a time domain rolling composite differential evolution algorithm; wherein, the time domain rolling composite differential evolution is recorded as TDRCDE.
Specifically, a day-ahead optimization scheduling model taking DPDR into consideration is constructed by considering the charge-discharge process of a storage battery based on a day wind/light predicted output and a day load predicted value in the day ahead and taking the lowest comprehensive operation cost of 24h in the future as an optimization target; on the dayAnd the inner stage is based on a day-ahead optimization scheduling scheme, a day-ahead time domain rolling optimization scheduling model based on the DDR-MPC is constructed by taking the lowest rolling time domain comprehensive operation cost as an optimization target, and the day-ahead scheduling scheme is corrected in time to reduce the scheduling deviation as much as possible. That is, the output and the actual output value of the unit are predicted in real time according to the wind and the light in the day, and the future is contained in every 1 time intervalNPerforming optimized scheduling increment control on the output of the diesel engine set and the charging and discharging of the storage battery at each time interval in the time domain of each time interval, and executing the obtained increment optimization result of the 1 st time interval of the rolling time domain as a real-time control instruction; meanwhile, a real-time feedback correction link is added, and the predicted output of the model is corrected through the actual measurement value to form closed-loop control. A block diagram of the micro-grid time domain rolling optimization scheduling model based on the day-ahead DPDR-intra-day DDR-MPC is shown in fig. 3.
The invention discloses a microgrid time domain rolling optimization scheduling method based on differential demand response model predictive control, which comprises the following steps: by combining the DDR method and the MPC method, the comprehensive operation cost of MPC-based microgrid rolling optimization scheduling can be obviously reduced, and the wind and light absorption capability of a microgrid system is improved; by providing a micro-grid multi-time scale scheduling strategy based on a DPDR-intra-day DDR-MPC considering demand response timeliness and difference, demand response resources can be fully utilized, output fluctuation of distributed power supplies of the micro-grid is reduced, scheduling errors caused by wind and light prediction errors are reduced, and reliability of optimal scheduling of the micro-grid is improved; the proposed time domain rolling composite differential evolution algorithm can efficiently solve the model, can remarkably improve the optimizing convergence speed and has good dynamic environment adaptability; when the microgrid is in an island operation mode, due to the fact that the microgrid lacks power support provided by an external network and is influenced by self capacity limit and uncertainty of output of renewable energy sources, the reliability of optimized scheduling is relatively poor, and the method provided by the invention can effectively improve the reliability of optimized scheduling of the island microgrid.
As a preferred embodiment of the present invention, it may also have the following additional technical features:
in this embodiment, in step 1, an objective function of the day-ahead optimized scheduling model is constructed, where the objective function is:
in the formula:
Τthe total number of time segments of the scheduling period is optimized for one day ahead,
ttaking a positive integer as a time interval;
Gthe number of diesel generator sets;
is composed of
tIn the first period
vThe dispatching cost of the diesel generating set is reduced,
vtaking a positive integer;
is composed of
tTime interval battery scheduling cost;
is composed of
tIn the first period
mDPDR scheduling cost of class load;
is composed of
tWind/light abandon penalty cost per period;
is composed of
tAnd the interaction cost of the microgrid and the external network in the time period.
In the DPDR scheduling before the day, wind curtailment/light curtailment punishment factors and an energy storage charging and discharging process are considered. The scheduling day integrated operation cost considers the DPDR cost and the wind/light abandon penalty cost.
In this embodiment, the mathematical model of each item cost in the objective function of the day-ahead optimization scheduling model is as follows:
wherein, the diesel generating set dispatching cost does:
in the formula:
α v 、
β v 、
λ v is as follows
vA diesel set scheduling cost coefficient;
is as follows
vA diesel generator set is arranged in
tActive power output in time intervals;
and
are respectively the first
vThe unit capacity installation cost, capital recovery factor and maximum output power of the diesel generating set;
and
are respectively the first
vThe running management cost coefficient, annual running hours and the capacity factor of the diesel generator set;
wherein, the battery scheduling cost is:
in the formula:
the unit capacity installation cost, capital recovery factor and capacity factor of the storage battery respectively;
and
the annual running hours and running management cost coefficients of the storage battery are respectively;
for the accumulator at tCharging and discharging power of a time period;
wherein, the DPDR scheduling cost is:
in the formula:
respectively the initial electricity price and the initial electricity consumption of the mth type load in the t period;
respectively indicating the electricity price and the electricity quantity of the mth load after the mth load participates in the DPDR at the time t;
wherein, abandoning wind/abandoning light penalty cost is:
in the formula:
punishing cost for unit air volume abandon;
respectively predicting the output power and the consumption of the wind generating set in the time period t in the day ahead;
punishment cost for unit light quantity abandon;
and
respectively predicting the output power and the consumption of the photovoltaic generator set in the period t in the day ahead;
the interaction cost of the micro-grid and the external grid is as follows:
in the formula:
exchanging power for the micro-grid and the external grid at a time t, wherein electricity purchasing is positive and electricity selling is negative;
trading prices for the amount of electricity for the period t.
In this embodiment, in step 1, constraints for constructing the day-ahead optimized scheduling model are included, where the constraints include:
and power balance constraint:
in the formula:
Gthe number of diesel generator sets;
is as follows
vA diesel generator set is arranged in
tThe active power output of the time period is,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is a wind generating set at the day before
tPredicted output power for the time period;
the predicted output power of the photovoltaic generator set in the period t before the day;
for microgrid and external network
tThe power is interacted in time intervals, wherein the electricity purchasing is positive and the electricity selling is negative;
is as follows
mClass load is in
tThe electric quantity after the time interval participates in DPDR;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
the upper and lower limits of the power of the diesel generator set are restricted:
in the formula:
the minimum output power and the maximum output power of the v-th diesel generator set are respectively.
And (3) climbing restraint of the diesel generator set:
in the formula:
the ascending and descending ramp rates of the v-th diesel generator set are respectively;
is the scheduled time difference.
And (3) charge and discharge restraint of the storage battery:
in the formula:
is a storage battery
tLoad of time periodAn electrical state;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
and
the maximum charging power and the maximum discharging power of the storage battery are respectively;
and
respectively charge efficiency and discharge efficiency of the storage battery;
the energy storage capacity of the storage battery;
and
maximum and minimum states of charge of the battery, respectively;
and (3) interactive power constraint of the microgrid and the external network:
in the formula:
respectively, the minimum and maximum values of the interaction power.
In this embodiment, in step 2, the method specifically includes:
step 2.1, establishing a prediction model based on a model prediction control method;
step 2.2, establishing a rolling optimization scheduling model;
and 2.3, introducing a feedback correction link, correcting the output of the micro-grid time domain rolling optimization scheduling model by using an actual measured value, and taking the actual measured value of the micro-grid time domain rolling optimization scheduling model as an initial value of a new round of rolling optimization to form closed-loop optimization control.
Specifically, MPC is mainly composed of three parts, namely, a prediction model, rolling optimization and feedback correction. The basic idea of DDR-MPC scheduling is to obtain an output optimal control sequence of a future prediction time domain according to the current state condition of the system, load information and a prediction model after a past DPDR and a day DDR, to apply the output of each distributed power supply, the storage battery and the load reduction optimization result obtained by a first control time domain of a control instruction issued and executed in the current time period to the next prediction time domain under the condition of participation of the DDR, to continuously roll the optimization process, and to correct the control output of the system at the time by using the actual measurement value of the current system. According to the invention, the rolling control time domain of the intraday optimal scheduling is set to be 1h, the rolling optimal scheduling time domain is set to be 4 time periods, and the time scale is 4 h. In practical application, the time domain of the rolling optimization scheduling and the time scale of the rolling control of the model can be flexibly set according to the actual prediction precision and the control requirement.
The explanation for introducing feedback correction is as follows: the output control sequence obtained by the prediction control is deviated from the actual output control sequence, and the output prediction error of the wind power photovoltaic is larger along with the increase of the time scale. Therefore, a feedback correction link needs to be introduced, so that the control process can correct the scheduling result error generated in the prediction process in time, and the scheduling precision of the micro-grid is improved.
In this embodiment, the prediction model is:
in the formula:
is a controllable unit
uIn that
tThe initial output value of the time interval is obtained by the open-loop scheduling in the day ahead,
utaking a positive integer as a whole, and taking the integer,
ttaking a positive integer;
is composed of
tTime period prediction future
Time-interval controllable unit
uIncremental output of (d);
is composed of
tTime period prediction future
Time interval controllable unit
uThe output value of (d);
Nto optimize the number of time-domain time segments;
and the climbing power value to be met by the output of each controllable unit in the adjacent prediction time period is obtained.
Specifically, the control variables are solved through rolling optimization, and then the optimal output values of each controllable distributed power supply, the load reduction amount and the storage battery in a future limited time domain are obtained.
In this embodiment, in step 2.2, an objective function of the rolling optimization scheduling model is constructed, where the objective function is:
in the formula:
is the current time period;
Nto optimize the number of time-domain time segments;
Gis the number of diesel generator sets;
Is composed of
tIn the first period
vThe dispatching cost of the diesel generating set is reduced,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is composed of
tTime interval battery scheduling cost;
is composed of
tInteraction cost of the micro-grid and the external network in a time period;
and
are respectively the first day
mClass load is in
tA DPDR scheduling cost and an IDR scheduling cost of a period;
is composed of
tThe air volume is abandoned in a time interval,
,
and
are respectively a wind generating set in the day
tThe output power and actual consumption of the time period;
in order to discard the amount of light in the day,
,
and
are respectively a solar photovoltaic unit
tThe output power and actual consumption of the time period;
punishment cost is given to unit air volume abandonment,
punishment cost for unit light quantity abandon;
the DPDR scheduling cost is as follows:
in the formula:
are respectively the first
mClass load is in
tElectricity price and electricity quantity after the time slot participates in DPDR;
are respectively the first
mClass load is in
tThe electricity price and the load value after the time interval is regulated before the day and then participates in the DPDR;
an Incentive Demand Response (IDR) is that a scheduling mechanism cuts off the load of a user and gives the user certain compensation according to the cut-off load amount, so that the user can respond to system scheduling in time. The IDR scheduling cost is as follows:
in the formula:
is as follows
mClass load is in
tThe actual load reduction of the time interval;
is as follows
mClass I of load
kStep quotation corresponding to the reduction of the grade load;
is as follows
mClass I of load
kStep-reducing load interval;
Kis prepared by reacting with
Corresponding step quote rating.
Specifically, in the scheduling stage in the day, the minimum rolling time domain comprehensive operation cost is taken as an objective function, and the scheduling cost of the DDR is considered in the cost, wherein the scheduling cost of the DDR includes the scheduling cost of the DPDR and the IDR. The solution time length is changed from 24 hours to the time length required by a future section of the rolling time domain. In order to embody the significance of the day-ahead scheduling, the unit output plan determined by the day-ahead scheduling and the charge-discharge state of the storage battery are kept.
In this embodiment, in step 2.2, constraints for constructing the rolling optimization scheduling model are included, and the constraints are:
power balance constraint
In the formula:
Gthe number of diesel generator sets;
is as follows
vA diesel generator set is arranged in
tThe active power output of the time period is,
ttaking a positive integer as a whole, and taking the integer,
vtaking a positive integer;
is a wind generating set in the sun
tAn output power of the time period;
is a photovoltaic unit in the sun
tTime periodThe output power of (d);
for microgrid and external network
tThe power is interacted in time intervals, wherein the electricity purchasing is positive and the electricity selling is negative;
is as follows
mClass load is in
tThe load value after the time interval is regulated day before and then participates in the DPDR;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
for the user
mIn that
tThe actual load reduction of the time interval;
upper and lower IDR bound
In the formula:
are respectively the first
mThe minimum value and the maximum value of the reduction amount of the class load;
the upper and lower limits of the power of the diesel generator set are restricted:
in the formula:
the minimum output power and the maximum output power of the v-th diesel generator set are respectively;
and (3) climbing restraint of the diesel generator set:
in the formula:
are respectively the first
vThe ascending and descending climbing rates of the diesel generating set;
is a scheduled time difference;
and (3) charge and discharge restraint of the storage battery:
in the formula:
is a storage battery
tA state of charge of the session;
and
are respectively a storage battery
tCharging power and discharging power of a time period;
and
the maximum charging power and the maximum discharging power of the storage battery are respectively;
and
respectively charge efficiency and discharge efficiency of the accumulatorElectrical efficiency;
the energy storage capacity of the storage battery;
and
maximum and minimum states of charge of the battery, respectively;
and (3) interactive power constraint of the microgrid and the external network:
in the formula:
respectively, the minimum and maximum values of the interaction power.
In this embodiment, in step 3, a rolling optimization strategy is introduced into a composite differential evolution CDE algorithm to construct a TDRCDE algorithm, where the composite differential evolution is recorded as CDE, and specifically, the dynamic optimization process of the TDRCDE algorithm is as follows:
step 3.1, set the population size to
Optimizing the number of time-domain time segments to
NThe maximum number of iterations is
The total time period is
TInitialization of
tTime interval population
Wherein
Representing the th in the population at time t
(ii) individuals;
the total number of the controllable units
UAnd optimizing the number of time-domain time-segments
NBy using
U×
NThe individual elements comprise the output of a diesel generator set, the charge and discharge amount of a storage battery and the load reduction amount;
step 3.2, in the optimization stage
tThe time interval takes the actual output value of each currently known controllable unit as an initial value based on the future
tTo
t+The latest wind and light output prediction data of 4 time periods are used for optimally designing the output force value of each controllable unit of 4 future time periods obtained by day-ahead optimal scheduling
As a reference value;
step 3.3, the optimal rolling optimization adjustment quantity of the force output values of all the controllable units in the scheduling time domain in 4 future time periods is obtained by using a CDE algorithm with the lowest comprehensive running cost of the micro-grid rolling time domain as a target
(ii) a In the CDE operation, the population individuals are sorted according to the principle that the lower the comprehensive operation cost is, the higher the fitness is, the population is divided into a dominant population and a subordinate population according to the division ratio of 1:1, the dominant and subordinate populations are respectively subjected to variation by using two different strategies of random variation and optimal solution variation to give consideration to the convergence speed and the individual diversity, wherein a cross probability factor and a variation scale factor can be respectively set to be 0.85 and 0.5; wherein, the random variation is represented as DE/rand/1 variation, and the variation is represented as DE/best/1 variation based on the optimal solution.
Step 3.4, carrying out merging recombination on the good and bad clusters to obtain new clusters, and continuing iteration on the clusters
g=
g+1, if
g<
When the bar is satisfied, return to step 3.3Piece
g=
Then, optimizing to obtain optimal population
Outputting the optimal value of the current iteration population
(ii) a And will predict the future made by model scheduling
4Sequence of optimal force output values of each controllable unit in each time period
For updating the sequence of optimally planned force values for each controllable unit
;
Step 3.5, dispatching time domain to continue advancing
t=
t+1 if the condition is satisfied
t=
TWhen the optimal value is obtained, the sorting of the optimized and combined population is stopped; if the condition is not met, the method goes to step 3.1, and the optimal population according to the last rolling optimization process is obtained
To construct an initialization population
And then, obtaining a new generation of population through the variation crossover operation of differential evolution, and repeating the steps until the conditions are met to obtain the optimal value of the comprehensive operation cost of the micro-grid rolling time domain.
Specifically, a differential evolution algorithm (DE) has been widely used in an optimal scheduling problem in a power system because of its characteristics of good convergence rate, stability, high efficiency, and the like. However, in the later period of evolution, the traditional DE algorithm still has the characteristics of individual diversity reduction and the like. The CDE algorithm mainly comprises operations of sequencing population individuals, dividing populations into good and bad, performing composite differential evolution, recombining populations and the like. By mutually complementing the advantages of different variation strategies, the convergence rate and diversity of individuals can be simultaneously considered. The micro-grid time domain rolling optimization scheduling model has high dimensionality, real-time performance and multi-constraint performance. The feasible solution of the method also has a dynamic change process when the scheduling time domain changes. The conventional CDE algorithm cannot fully utilize the historical population and the historical optimal solution information when the scheduling time domain changes, cannot quickly construct the initial population in a new environment, and cannot reduce the difference between the initial population and the optimal population in the new environment. Therefore, the invention introduces a rolling optimization strategy into a CDE algorithm, constructs the CDE algorithm based on dynamic optimization, and provides a new time domain rolling differential evolution (TDRCDE) algorithm. The flow chart of the TDRCDE algorithm constructed by the invention is shown in FIG. 2.
The above additional technical features can be freely combined and used in superposition by those skilled in the art without conflict.
It is to be understood that the present invention has been described with reference to certain embodiments, and that various changes in the features and embodiments, or equivalent substitutions may be made therein by those skilled in the art without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.