Risk-based planning of sharing power plant units in the presence of wind power plants and reserve pumps

Dissertation to receive a master's degree in electricity, power systems orientation

Abstract:

     In this thesis project, a new analytical approach for planning electric energy production and determining the amount and storage location of rotating storage corresponding to the risk level of subscriber load points by profit/cost analysis in the program for optimizing the entry and exit of power plant units It is suggested that, in addition to thermal units, they are also present in the production sector of pumped-storage hydropower units and wind farms. We consider the prediction of wind speed-power scenarios for wind farms and first-order forced exits of production units as uncertainties of network operation conditions in order to evaluate the reliability of the combined production and transmission system (HLII level). It is assumed that the rotating reserve is provided in each operation planning period according to the conditions of the shared market with the simultaneous settlement of energy and reservation by the synchronous no-load capacity of the thermal production units of the network. The expected unsupplied energy cost of subscribers' load points (EENScost) has been selected as a possible index of power system risk assessment to provide a balance between the benefits obtained from the purchase of rotating storage against its purchase cost in each 1-hour period of network operation planning according to the shared market with simultaneous settlement. The proposed algorithm is tested on a sample 5-bus network, and finally, the efficiency and effectiveness of the proposed algorithm by performing simulation studies and sensitivity analysis by changing some important reliability parameters, such as the value of the lost load of subscribers in different bus networks, the failure rate of production units, wind speed-power forecast scenarios for wind farms, etc. It will be proved according to the conditions of the share market the next day.   

Introduction

       In recent years, due to increasing concerns regarding global warming and the call for decarbonization of electric energy production sources, commercial interest in the presence and development of the capacity of storage pumped hydropower plants in the network has increased. To save energy, water is pumped from the lower reservoir to the upper reservoir by pumps, and to use it, the unit, like a hydropower plant, sends energy to the lower reservoir through water turbines. These storage pump units can participate separately in the energy sales or reserve market, or they can be integrated by a company that has wind or conventional power plants or both. With the presence of water storage pump units in the network, the Unit Commitment optimization program corresponding to the conditions of the shared energy market sees changes in the objective function and technical limitations, which must be modeled according to the technical terms of the new conditions. Analytical and innovative methods can be used to solve this problem under new conditions. The studies conducted in this field with the analytical method have taken into account the uncertainty of wind speed-power prediction, while for the planning of production and the amount of rotating storage under shared market conditions, considering the reliability of the combined production and transmission system, valid possible events such as the forced exit of production units from the transmission network (cost caused by load interruption due to the change of network load distribution during emergency conditions) as uncertainty can bring us closer to more accurate modeling and optimal solution of the aforementioned problem, as a result of Expenditure of additional costs for the purpose of allocating revolving reserve in excess of the need or uneconomical dispatching of the load on the production units hindered and thus the maximum profit from the settlement of the shared market is reached to its partners. In traditional power systems and today's restructured power systems, in order to save fuel consumed by thermal power plants, a program called unit commitment is implemented to plan the joint entry and exit of power plant units in order to supply the load in such a way that without exceeding the system and physical limitations of the network, the cost of energy production is minimal or the profit of market partners is maximized. This planning in today's systems is based on information such as the sales offer submitted by the owners of the power plant units and the consumption offer received by the load owners under normal conditions for the power system. Considering that the two goals of maintaining the reliability of the power system (risk management) and economic benefits from active power exchanges in the electricity market are in competition with each other.Considering that the two goals of maintaining the reliability of the power system (risk management) and the economic benefits resulting from active power exchanges in the electricity market are in competition with each other in such a way that increasing the amount of exchanges in order to increase the profits of the market partners leads to exceeding the reliability criteria and endangers the security of the system, and on the other hand, increasing the system reliability margins in order to reduce the possible costs of energy outages (transaction violations) due to the occurrence of random events such as the forced withdrawal of large power plant units or transmission lines. and so on. It will lead to restrictions in power exchange and competitive market environment, as well as an increase in operating costs. The independent operator of the ISO system, as the person responsible for maintaining system reliability and the manager of the electricity market, must perform energy market clearing (acceptance and rejection of exchanges) as well as the purchase of ancillary services (exploitation reserve) in each period of daily operation planning in such a way that the total costs of the entire system, including the operation cost and reliability costs, are minimized and as a result social welfare is maximized. Therefore, our goal in this thesis project is to present a new analytical algorithm according to the reliability criterion of the combined generation and transmission system (HLII level) to solve the UC problem with the presence of wind units and storage pumps in addition to thermal units. To achieve this goal, a new formulation for the load point risk index of subscribers is presented by evaluating the reliability of the combined production and transmission system with regard to the existing uncertainties including the variability of wind speed and the forced exit of heat and water storage pump (PSH) production units. The objective function is to maximize the difference in total income, including energy production on all types of power plants in the shared market, from the total costs, including the total fuel cost of thermal power plants and the fixed cost of operation of storage pump units and the cost, as well as the maintenance of the rotating reserve of the risk of subscribers' load points, taking into account all the limitations of operation. In this way, by solving this problem, the entry and exit method of thermal, wind and water storage pump units, in addition to the economic distribution of load on them, the amount and location of rotating storage, as well as the cost of the optimal risk of load points in planning the operation of the system under shared market conditions will be determined. rtl;> Since 2000, interest in the development of PHS facilities has been revived around the world, and in 2009 hundreds of pumped storage plants with a capacity of 127 GW are in operation worldwide. Currently, Japan has the highest PHS capacity in the whole world. Developers are actively pursuing new PHS projects around the world. 76 GW PHS excess capacity of the world is expected in 2014. China has the most pioneering plans in this field. The Chinese government has identified 247 potential PHS sites with a total capacity of 310 GW and is expected to increase the installed capacity of PHS to 50 GW by 2020. Since Japan currently has the highest volume of PHS installations in the world, Japanese electric companies are continuously increasing and developing PHS plans. Following the special attention of these countries in developing the capacity of pumped storage power plants, extensive research has been carried out in the field of production planning and how these units are placed in the circuit next to conventional thermal units (base load units) and wind farms, mainly to solve the UC problem according to the conditions of establishing long-term, medium-term and short-term electricity markets. rtl;">Storage pump power plant modeling and simulation [1].

Integrated operation of wind power plant and storage pump to participate in the electricity market [2].

Planning the optimal use of wind-storage pump production resources in the restructured power system using fuzzy modeling [3].

Planning and coordination of pumped-storage and wind power plants taking into account uncertainty in forecasting wind load and power [4].