Peak Shaving Benefits Assessment of Renewable Energy Source Considering Joint Operation of Nuclear and Pumped Storage Station

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CUE2018-Applied Energy Symposium and Forum 2018: Low carbon cities and Applied Energy Symposium and Forum 2018: Low carbon cities and urban energy systems, CUE energy systems, 5–7 June 2018, Shanghai, China 2018, 5–7 June 2018,urban Shanghai, China The 15th International Symposium on District Heating and Cooling Peak Energy Shaving Benefits Assessment of Renewable Source Applied Symposium and Forum 2018: Low carbon cities and urbanEnergy energy systems, CUE 2018, 5–7 June 2018, Shanghai, China Considering Joint Operation of Nuclear and Pumped Storage Station

Assessing the feasibility of using the heat demand-outdoor temperature function a long-term demand forecast a b bSource Peak Shaving Benefits Assessment ofdistrict Renewable Energy Ying Gong , Changshu Tanb*, for Yannan Zhanga, Yiping Yuanb,heat Lei Zhou , Yan Li , Jianxue b Wang Considering Joint of aNuclear Station b c I. Andrića,b,c *, A.Operation Pinaa, P. Ferrão , J. Fournierand ., B.Pumped LacarrièrecStorage , O. Le Corre a

Huadong Engineering Corporation Limited, Gaojiao Road 201, Hangzhou, 311122, China

afor Engineering b and Policy a Superior b Rovisco b IN+ Center Innovation, Technology Research - Instituto Av. Pais 1, b1049-001 Portugal School of Electrical ，Xi’an University, Xianning West Road 28,Técnico, Xi’an, 710049, China Ying Gong , Changshu TanJiaotong *, Yannan Zhang , Yiping Yuan , Lei Zhou , Yan Lisbon, Lib, Jianxue Veolia Recherche & Innovation, 291 Avenue Dreyfous Daniel, 78520 Limay, France b Wang Département Systèmes Énergétiques et Environnement - IMT Atlantique, 4 rue Alfred Kastler, 44300 Nantes, France a

b

c

aAbstract

Huadong Engineering Corporation Limited, Gaojiao Road 201, Hangzhou, 311122, China School of Electrical Engineering，Xi’an Jiaotong University, Xianning West Road 28, Xi’an, 710049, China

b

In renewable energy power system, it has been the focus of attention to improve the system’s flexibility to promote renewable Abstract energy utilization and low carbon emission. To improve the adjustment capability of power system integrating renewable energy, a new method that considers joint operation of nuclear power plants and pumped storage stations is proposed. First, to take the Abstract District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the operational characteristics of nuclear power plants and pumped storage stations into account, the operational models of the two greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat kinds of power stations are system, constructed. anfocus assessment modeltothat is to evaluate the benefits of different peak shaving In renewable energy power it hasSecond, been the of attention improve the system’s flexibility to promote renewable sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, source is constructed. Furthermore, a system benefitsthe assessment is presented. the case ofrenewable both nuclear and energy utilization and low carbon emission. Toofimprove adjustmentindices capability of power Finally, system integrating energy, prolonging the investment return period. storagethat stations participating in peak of shaving adjustment is analyzed, verifying the stations effectiveness of the proposed apumped new method considers joint operation nuclear power plants and pumped storage is proposed. First, to method. take the The main scope of energy this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand Keywords: renewable low carbon nuclear powerstorage plant; pumped station; peak operational characteristics source; of nuclear poweremission; plants and pumped stationsstorage into account, theshaving. operational models of the two forecast. © The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 Copyright 2018 Elsevier Ltd. All rights reserved. kinds of power stations are constructed. Second, an assessment model that is to evaluate the benefits of different peak shaving Selection responsibility thetypology. scientificThree committee of the CUE2018-Applied Energy and buildingsand thatpeer-review vary in bothunder construction periodofand weather scenarios (low, medium, high) Symposium and three district source is constructed. Furthermore, a system of benefits assessment indices is presented. Finally, the case of both nuclear and Forum 2018: Low carbon cities and urban energy systems. renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were 1. Introduction pumped storage stations participating in peak shaving adjustment is analyzed, verifying the effectiveness of the proposed method. compared with results from a dynamic heat demand model, previously developed and validated by the authors. Keywords: renewable energy source; low carbon emission; nuclear power plant; pumped storage station; peak shaving. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications With of China’s economy, the needscenarios of electricity is increasing the same time, renovation but now (the errorthe in rapid annualdevelopment demand was lower than 20% for all weather considered). However,atafter introducing thermal power plants still constitute the majority of China’s power supply, causing the problem of massive resource scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). 1. Introduction gas emission. Nowadays China has been vigorously developing renewable energy and nuclear consumption The value of and slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the energy [1-3]. Tonumber ensureoftheheating frequency of power the source load ofon thethe system must beofbalanced in decrease in the hoursquality of 22-139h duringsystem, the heating season and (depending combination weather and With rapid of economy, the and need of electricity is the same time, but on now renovation scenarios considered). OnChina’s the other hand, function intercept increased forincreasing 7.8-12.7% per decade the all time. the Since the development output of renewable energy is random unstable, it is necessary thatat other kinds(depending of power, like thermal plants still constitute the could majority of balance, China’s power supply, causing thefor problem massive resource coupledpower scenarios). The values be used to modify function parameters the scenarios considered, and thermal power, shave peak tosuggested maintain the power butthe with the rapid development ofofnuclear power and consumption and gasofemission. Nowadays China has been vigorously developing renewable energy and nuclear improve the accuracy heat demand estimations.

energy [1-3]. To ensure the frequency quality of power system, the source and load of the system must be balanced in © time. 2017 The Authors. Published by Elsevierenergy Ltd. is random and unstable, it is necessary that other kinds of power, like all Since the output of renewable Peer-review under responsibility of the Scientific Committee of Thebut 15th International on District Heating and and thermal power, author. shaveTel.: peak to maintain power balance, with the rapidSymposium development of nuclear power * Corresponding 18710958821; fax: the 029-82665489. Cooling. E-mail address: [email protected]

This work was supported by the Study on Benefits Evaluation of Pumped Storage Stations Project of Huadong Engineering Corporation Limited Keywords: Heat demand; Forecast; Climate change (Grant No. KY2016-02-10) * Corresponding author. Tel.: 18710958821; fax: 029-82665489. 1876-6102 Copyright © 2018 Elsevier Ltd. All rights reserved. E-mail address: [email protected] Selection and peer-review under responsibility of the Evaluation scientific committee the Applied Energy Symposium andEngineering Forum 2018: Low carbon cities This work was supported by the Study on Benefits of PumpedofStorage Stations Project of Huadong Corporation Limited and urban systems, CUE2018. (Grant No.energy KY2016-02-10) 1876-6102 © 2017 The Authors. Published by Elsevier Ltd. Peer-review under responsibility of the Scientific Committee of The 15th International Symposium on District Heating and Cooling. 1876-6102 Copyright © © 2018 2018 Elsevier Elsevier Ltd. Ltd. All All rights rights reserved. reserved. 1876-6102 Copyright Selection and peer-review under responsibility of the scientific committee of the CUE2018-Applied Energy Symposium and Forum Selection and peer-review under responsibility of the scientific committee of the Applied Energy Symposium and Forum 2018: Low carbon cities 2018: Low carbon cities and urban energy systems. and urban energy systems, CUE2018. 10.1016/j.egypro.2018.09.099

Ying Gong et al. / Energy Procedia 152 (2018) 953–958 Changshu Tan/ Energy Procedia 00 (2018) 000–000

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renewable energy power, the development space of thermal power is decreasing which reduces the peak shaving task for thermal generators, so the difficulty of peak shaving will increase continuously [4]. Of power system’s adjustment ability, the most important aspect is peak shaving ability. In order to alleviate the peak shaving problem, it is necessary that nuclear power plants assume part of peak shaving task [5-9]. According to the experience of power grid dispatch in some regions, peak shaving by nuclear power plants can not only maintain power balance efficiently, but also reduce thermal power’s losses significantly [10-14]. As nuclear power peak shaving technology has not yet fully matured, except for shaving peak by nuclear power alone, nuclear power can also cooperate with other kinds of peak shaving power plants, like pumped storage stations and cooperative operation can not only shave peak more flexibly and more economically, but also broaden peak shaving space [15-16], this paper mainly discuss the joint operation of nuclear power plants and pumped storage stations. In this paper, section Ⅱ describes the models of nuclear power plants and pumped storage stations, section Ⅲ presents the calculation process and proposes a benefits assessment system of peak shaving, section Ⅳ presents the results of an actual power grid using the proposed models and method, section Ⅴ outlines the conclusion of the research. 2. The models of nuclear power plants and pumped storage stations 2.1. Models of nuclear power plant In foreign countries, some nuclear power plants, mainly Pressured Water Reactor (PWR), have already had some experience of load track. In this paper, we build the model of PWR nuclear power plants for peak shaving. In design, PWR power stations are capable of daily load tracking and the rate of output change is usually (±5%Pn)/min [17]. The constraints of PWR power plants are as follow: Output constraint: N N (1) Pmin  Pt N  Pmax 𝑁𝑁 𝑁𝑁 𝑁𝑁 Where 𝑃𝑃𝑡𝑡 is the output of nuclear power plant at time t, 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 and 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 are the minimum and maximum electrical 𝑁𝑁 𝑁𝑁 is about 40% to 50% of 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 [18]. output of the nuclear power plant, generally speaking, 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 Ramping constraint:

 Pt N  Pt N1  5% Pn   N N   Pt 1  Pt  5%Pn

(2)

Where 𝑃𝑃𝑛𝑛 is the rated output of PWR power plant. This constraint means that PWR power plants can only change the output at a maximum rate of 5%𝑃𝑃𝑛𝑛 per minute. Actually, considering the depth and speed limits of peak shaving, in most cases, PWR nuclear power plants use "12-3-6-3" daily load tracking mode to shave peak, that is to say, full-power operation for 12 hours, 3 hours for power reduction, 6 hours of continuous operation at low power level, and 3 hours of power up to full power operation [18]. 1.2

output/p.u.

1 0.8 0.6 0.4

0.2 0

9:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00 1:00

3:00

5:00

7:00

9:00

Fig. 1. Daily output curve of PWR station at the mode of “12-3-6-3”.

The output curve of PWR station shown in Fig.1. is in compliance with grid load curve and the speed of PWR



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station output regulation is also small so this kind of operational mode has become the main peak shaving way of PWR power plants. 2.2. Models of pumped storage station Considering the natural conditions and operational characteristics, pumped-storage stations have the following operating constraints [19]: Unit output constraint: PS , g 0  Pt PS , g  xtPS , g Pmax

(3)

PS , d 0  Pt PS ,d  xtPS ,d Pmax

𝑃𝑃𝑃𝑃,𝑔𝑔

𝑃𝑃𝑃𝑃,𝑑𝑑 Where 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 and 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 are the station’s maximum pumping power and generating power respectively. 𝑥𝑥𝑡𝑡𝑃𝑃𝑃𝑃,𝑑𝑑 and are 0-1 variables which indicate whether the station is pumping or generating electricity, when the station is 𝑃𝑃𝑃𝑃,𝑔𝑔 equals to 1, pumping, 𝑥𝑥𝑡𝑡𝑃𝑃𝑃𝑃,𝑑𝑑 equals to 1, otherwise equals to 0 and when the station is generating power, 𝑥𝑥𝑡𝑡 otherwise equals to 0. Reservoirs’ capacity constraint: PS PS (4) Emin  EtPS  Emax 𝑃𝑃𝑃𝑃 𝑃𝑃𝑃𝑃 𝑃𝑃𝑃𝑃 Where 𝐸𝐸𝑡𝑡 is the station’s storage capacity at the moment of t, 𝐸𝐸𝑚𝑚𝑚𝑚𝑚𝑚 and 𝐸𝐸𝑚𝑚𝑚𝑚𝑚𝑚 are maximum storage capacity and minimum storage capacity respectively. Pumping-generation exclusive constraint: (5) xkPS,t , g  xkPS,t ,d  1 𝑃𝑃𝑃𝑃,𝑔𝑔 𝑥𝑥𝑡𝑡

This constraint means that pumped storage stations can’t pump and generate power at the same time. 3. Benefits assessment system of peak shaving under joint operation of PWR and pumped storage stations In order to assess the peak shaving benefits of the system under the joint operation of PWR power plants and pumped storage stations, in this paper the hourly operation of the two kinds of power is simulated and the main idea is to translate the long-term simulation problems of power system into a mathematical model [20]. In the mathematical mode, the objective function is the operational cost of the whole power system, including the cost of thermal generators, nuclear power plants and the penalty items of wind & solar curtailment and load shedding. The formula can be expressed as follow:

 min C

NN NW NS NL  NC  W  0 S  0 C on N L W        Pi ,St  f P Q u Y P  P  P P          i ,t i i ,t i ,t L  i ,t W i ,t i ,t S  Pi ,t t 1  i 1 i 1 i 1 i 1 i1  T













(6)

Where 𝑁𝑁𝐶𝐶 , 𝑁𝑁𝑁𝑁 , 𝑁𝑁𝐿𝐿 , 𝑁𝑁𝑊𝑊 and 𝑁𝑁𝑆𝑆 are the number of thermal generators, nuclear power plants, loads, wind farms and 𝐶𝐶 𝐶𝐶 is the output of thermal generator 𝑖𝑖 at time 𝑡𝑡 and 𝑓𝑓(𝑃𝑃𝑖𝑖,𝑡𝑡 ) is the coal consumption cost of it. 𝑄𝑄𝑖𝑖𝑜𝑜𝑜𝑜 is solar stations. 𝑃𝑃𝑖𝑖,𝑡𝑡 𝑁𝑁 the startup cost of thermal generator 𝑖𝑖 and 𝑢𝑢𝑖𝑖,𝑡𝑡 is the state variate of it. 𝑃𝑃𝑖𝑖,𝑡𝑡 is the output of nuclear power plant 𝑖𝑖 at 𝑊𝑊(0)

𝑁𝑁 𝐿𝐿 time t and 𝑌𝑌(𝑃𝑃𝑖𝑖,𝑡𝑡 ) is the cost of it. 𝑃𝑃𝑖𝑖,𝑡𝑡 is the amount of load shedding at time t. 𝑃𝑃𝑖𝑖,𝑡𝑡 𝑆𝑆(0)

𝑊𝑊 , 𝑃𝑃𝑖𝑖,𝑡𝑡 is the rated output and actual

𝑆𝑆 output of wind farm 𝑖𝑖 at time 𝑡𝑡, 𝑃𝑃𝑖𝑖,𝑡𝑡 , 𝑃𝑃𝑖𝑖,𝑡𝑡 is the rated output and actual output of solar station 𝑖𝑖 at time 𝑡𝑡. 𝜌𝜌𝐿𝐿 , 𝜌𝜌𝑊𝑊 , 𝜌𝜌𝑆𝑆 are the penalty factor of load shedding, wind curtailment and solar curtailment. The constraints of the optimization problem are as follow: Constraints of thermal generators’ output: C C (7) Pmin  Pi C  Pmax 𝐶𝐶 𝐶𝐶 Where 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 , 𝑃𝑃𝑚𝑚𝑚𝑚𝑚𝑚 are the minimum and maximum electrical output of unit 𝑖𝑖. Ramping constraints of thermal generators:

PD  Pt C  Pt C1  PU Where 𝑅𝑅𝑈𝑈 is ramping rate of thermal units and 𝑅𝑅𝐷𝐷 is lower ramping rate of thermal units. Commitment constraints of thermal generators:

(8)

Ying Gong et al. / Procedia Energy Procedia 152 (2018) 953–958 Changshu Tan/ Energy 00 (2018) 000–000

4956

dtC  xtC  xtC1  utC

(9) and are two exclusive characteristic variables, when thermal generator is in operation, 𝑑𝑑𝑡𝑡𝐶𝐶 equals to Where 0, 𝑢𝑢𝑡𝑡𝐶𝐶 equals to 1, oppositely, when thermal generator in out of service, 𝑑𝑑𝑡𝑡𝐶𝐶 equals to 1 and 𝑢𝑢𝑡𝑡𝐶𝐶 equals to 0. Constraints of renewable energy’s output: W  0 W  0  Pi ,t  Pi ,t (10)  S  0 S   0 P P  i , t i , t  This equation means the actual outputs of wind farms and solar stations can’t exceed the rated outputs of them. Constraints of power balance: 𝑑𝑑𝑡𝑡𝐶𝐶

𝑢𝑢𝑡𝑡𝐶𝐶

NN

NC

NW

NR

NS

ND

 Pi,Nt   Pi,Ct   Pi,Rt   PiW,t   Pi,St   Pi,Dt

(11)

i 1 i 1 i 1 i 1 i 1 i 1

𝑅𝑅 The output of all kind of power should be equal to the load and 𝑁𝑁𝑅𝑅 is the number of hydropower stations and 𝑃𝑃𝑖𝑖,𝑡𝑡 is the output of hydropower station 𝑖𝑖 at time 𝑡𝑡. To assess power system’s peak shaving benefits, in this paper we build a new benefits assessment system of peak shaving which include three aspects: technical index, environmental index and economical index.

 Technical index: peak shaving capacity Peak shaving capacity of a power system is consisted of four parts: peak shaving capacity of thermal generators, hydropower stations, pumped storage stations and nuclear power plants. The formula is as follow: NC

NR

NN

NP

C R P N P    Pi ,max  Pi ,Ct     Pi ,max  Pi ,Rt     Pi ,max  Pi ,Pt     Pi ,max  Pi ,Nt 

(12)

i 1 i 1 i 1 i 1

𝐶𝐶 𝑅𝑅 𝑃𝑃 𝑁𝑁 Where 𝑃𝑃𝑖𝑖,𝑚𝑚𝑚𝑚𝑚𝑚 , 𝑃𝑃𝑖𝑖,𝑚𝑚𝑚𝑚𝑚𝑚 , 𝑃𝑃𝑖𝑖,𝑚𝑚𝑚𝑚𝑚𝑚 and 𝑃𝑃𝑖𝑖,𝑚𝑚𝑚𝑚𝑚𝑚 are the maximum output of thermal generator, hydro generator, pumped storage station and nuclear power plant.

 Environment index: wind & solar curtailment Wind & solar curtailment include curtailment of wind and solar and the calculation formula is as follow: NS W  0 W i ,t i ,t i 1 i 1

 W

NW

 P

P

   P    P  S 0 i ,t

S i ,t

(13)

 Economical index: operational cost To assess the operational costs of the system under different peak shaving capabilities, in this paper the operational cost of power system is supposed just as (6). 4. Case studies and results In order to illustrate the benefits of peak shaving by joint operation of nuclear power plants and pumped storage stations, in this section an actual power grid is used as an example to assess its peak shaving benefits in different scenarios. Of the actual power grid, the installed capacity of thermal power is 71058MW, accounting for 80% of the system’s installed capacity and the installed capacity of pumped storage stations and nuclear power plants are 1320MW and 1200MW respectively. In this paper two scenarios are chosen, scenario 1 is the system shaving peak by pumped storage stations alone and scenario 2 is the system shaving peak by PWR power plants and pumped storage stations together and the overall system statistics are shown as follow: Table 1. Overall statistics of different scenarios. Technical index Scenario 1

Environmental index

Economical index

Peak shaving capacity/MW

Wind curtailment/GWh

Solar curtailment/GWh

Operational cost/billion RMB

13439

880.4

248.9

45.03



Ying Gong et al. / Energy Procedia 152 (2018) 953–958 Changshu Tan/ Energy Procedia 00 (2018) 000–000

Scenario 2

15926

679.2

957 5

97.2

44.33

30

30

25

25

20

20

15

15

10

10

5

5

0

1

2

3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 peak shaving capacity of scenario 1 peak shaving capacity of scenario 2 thermal output of scenario 2 thermal output of scenario 1

peak shaving capacity/GW

output of thermal generators/GW

In general, peak shaving by PWR power plants and pumped storage stations have better performance of load shedding, resource curtailment and operational cost. Due to the peak shaving effect of nuclear power plants, thermal generators can operate in low output mode, so the whole system’s peak shaving capacity is higher, up to 15926 MW, the output of thermal generators and system’s peak shaving capacity of a typical day is as follow:

0

Fig. 2. Output of thermal generators and peak shaving capacity of a typical day in July.

With nuclear power plants participating in peak shaving in scenario 2, the peak shaving capacity of the whole system has increased 2487MW hourly on average, the power system’s ability to meet the load demand has improved and the possibility of load loss has reduced. To analyse the environmental benefits of nuclear power brings, the monthly results of natural resource abandon are shown as follow: Wind&Solar Curtialment/GWh

300 250 200 150

100 50 0

1

2

3

4

5 6 scenario 1

7 8 scenario 2

9

10

11

12

Fig. 3. Monthly wind & solar curtailment with/without PWR adjustment.

From Fig.3, it can see that in scenario 2, the natural resource curtailment has greatly reduced. Since thermal generators and pumped storage stations can regulate their output flexibly to make sure renewable energy generate power as much as possible, renewable power plants can operate in high output mode which reduces thermal power’s output, as a result, the system’s operational cost will reduce. On the other hand, due to the forced start-up of some thermal generators in winter, the power generation space for renewable energy is squeezed, so in winter natural resource curtailment is higher than other seasons. From the results, in scenario 2 renewable power plants generate more than 300GWh power, which means in scenario 2, thermal power plants can save more than 98820 tons of coal a year, and emit 305551 tons less CO 2, 9190 tons less SO2 and 4545 tons less NO2. Furthermore, since the cost of thermal generators constitutes the majority of the system’s operational cost, in scenario 2 the overall cost has reduced 6.93 billion RMB. In conclusion, nuclear power peak shaving can bring considerable environmental and economic benefits.

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5. Conclusion As technology continues to mature, nuclear power participation in peak shaving becomes possible. This paper builds the model of nuclear power plants and pumped storage stations in peak shaving and proposes a mathematical model to analyse the joint operation between nuclear power plants and pumped storage stations. To estimate the benefits of peak shaving, a new peak shaving benefits assessment system is presented which includes technical index, environmental index and economical index. Furthermore, an actual power grid is used to demonstrate the benefits of the proposed method. From the results, it shows that peak shaving by the joint operation of nuclear power plants and pumped storage stations can not only increase peak shaving capacity, but also reduce coal consumption and emission of greenhouse gases and bring considerable economic benefits. References [1] Ye, Qizhen. China's nuclear power development after Fukushima nuclear power plant accident. Proceedings of the CSEE, 32(11): 1-8, 2012. [2]Zhang, Yao; Wang, Jianxue. GEFCom2014 probabilistic solar power forecasting based on k-nearest neighbor and kernel density estimator. IEEE Power & Energy Society General Meeting, 2015. [3]Wang, Jianxue; Ahmed Faheem Zobaa; Huang, Chengcheng. Day-ahead allocation of operation reserve in composite power systems with largescale centralized wind farms. Journal of Modern Power Systems & Clean Energy, 4(2): 238-247, 2016. [4]Wang, Jun; Zhao, Jie; Ye, Xiaoli. Safety constraints and optimal operation of large-scale nuclear power plant participating in peak load regulation of power system. IET Generation, Transmission & Distribution, 11(13): 3332-3340, 2017. [5]Akin, H.Levent; Altin, Vural. Rule-based fuzzy logic controller for a PWR-type nuclear power plant. IEEE Transactions on Nuclear Science, 38(2): 883-890, 1991. [6]Yim, Man-Sung; Christenson, John M. Application of optimal control theory to a load-following pressurized water reactor. Nuclear Technology, 100(3): 361-377, 1992. [7]Khajavi, Mehrdad N.; Menhaj, Mohammad B.; Suratgar. Amir A. A neural network controller for load following operation of nuclear reactors. Annals Nuclear Energy, 29(6): 751-760, 2002. [8]Kirby, Brendan; Kueck, John; Leake, Harvey. Nuclear generating stations and transmission grid reliability. 39th North America Power Symposium: 279–287, 2007. [9]Khorramabadi, Sima Seidi; Boroushaki, Mehrdad; Lucas, Caro. Emotional learning based intelligent controller for a PWR nuclear reactor core during load following operation. Annals Nuclear Energy, 35: 2051-2058, 2008. [10]Saif, Mehrdad. Novel approach for optimal control of a pressured water reactor. IEEE Transactions on Nuclear Science, 36(1): 1317-1325, 1992. [11]Forsberg, Charles W. Economics of Meeting Peak Electricity Demand Using Hydrogen and Oxygen from Base-Load Nuclear or Off-Peak Electricity. Nuclear Technology, 166(1):18-26, 2009. [12]Berkovich, V.M.; Gorokhov, V.F; Tatarnikov, V.P. Possibility of regulating the capacity of a power system by means of nuclear power plants. Teploenergetika, 6:16-19, 1974. [13]Ebert, David D. Practicality of and benefits from the application of optimal control of pressured water reactor maneuvers. Nucl Technol, 58(2): 218-232, 1982. [14]Zhao, Jie; Liu, Dichen; Yang, Nan. Operation mode and benefits of nuclear power plant participating in peak load regulation of power system. Power System Technology, 36(12):250-255, 2012. [15]Bai, Jianhua; Jia, Yubin; Wang, Yaohua. Study on combined operation of nuclear power plant and pumped storage power plant. Electric Power Technologic Economics, 19(6): 36-40, 2007. [16]Zhou, Wei; Hu, Shubo; Sun, Hui. Joint generation dispatch of power system with nuclear power units participating in peak load regulation. International Conference on Smart Grid and Clean Energy Technologies: 324-327, 2016. [17]Cui, Zhenhua; Wang, Yuanlong; Liao Zhongyue. Research on the control system simulation of pressured water reactor (PWR) nuclear power plant. Nuclear Power Engineering, 20(5): 389-394, 1999. [18]Zhao, Jie; Liu, Dichen; Lei, Qingsheng. Analysis of nuclear power plant participating in peak load regulation of power grid and combined operation with pumped storage power plant. Proceedings of the CSEE, 31(7): 1-6, 2011. [19]Attya, Aymanakryaha T.; Hartkopf, Thomas. Utilising stored wind energy by hydro-pumped storage to provide frequency support at high levels of wind energy penetration. IET Generation, Transmission & Distribution, 9(12): 1485-1497, 2015. [20]Cheng, Hongliang. Long-term power system operation simulation including large-scale renewable energy. Xi’an:Xi’an Jiaotong University, 2015.