Power system planning with optimal reservoir system management : the case of Nepal | |
| Author | Basnyat, Divas B. |
| Call Number | AIT Diss. no. WM-97-01 |
| Subject(s) | Hydrothermal electric power systems Water resources development--Nepal |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. WM-97-01 |
| Abstract | The main objectives of this research are to evaluate hydrothermal power system planning and operation models, and to develop a suitable model for a hydro (hydropower) dominated power system. The traditional power system planning models are seen to be more appropriate for thermal dominated systems. The role of hydropower and its operational benefits vis-a-vis thermal systems have only been partially recognized in the power sector (electricity supply). This research proposes an operational planning methodology that represents chronological aspects of hydroelectric units (especially for reservoir operation), hydrological stochasticity and serial correlation, uncertainties in equipment availability, and random loads (electricity demand). The use of two hierarchical sub models, namely a hydro scheduling (HS) model and a probabilistic production costing (PPC) model, for hydrothermal operation makes it convenient to model the objectives, constraints, and characteristics of both the water and power sectors. The objective of the HS model (reservoir operation) is to minimize the power system operation cost (the thermal generation cost and the cost of energy not served). The stochastic dynamic programming (SDP) algorithm is used to solve the HS model. The concept of 'water value' is used to evaluate the reservoir states from one stage to the other. The HS model can also consider other multiple purposes like irrigation, flood control, low flow augmentation, etc. Sequential optimization technique is used by the HS model to handle systems with multiple reservoirs. The PPC model is based on a modified Baleriaux scheme suitable for a mixed hydrothermal simulation. The model makes a special distinction between energy limited hydropower units with different storage capacities and the capacity limited thermal units. The model calculates the system operation costs and reliability levels in terms of loss of load probability (LOLP) and expected energy not served (EENS) for different states of the HS model. An important output of the combined use of the two hierarchical models are the operation policies of the reservoir systems. The perfo1mance of the operation policies so derived are evaluated by system operation simulation using synthetically generated inflows and the developed PPC model. The hydro energy generation, reservoir storage, thermal generation and other variables over the simulation period are then statistically analyzed. The methodology developed is applied to the case of a hydro dominated power system of Nepal. It is used to carry out operational planning studies, to evaluate the economics of hydro and thermal units in the power systems, to derive the operation policies of the reservoir systems and to study the consequences of the policies on the different water uses. The methodology is also used to find the optimal design (installed capacity) of a hydroelectric plant considering the present and future scenarios of the power system. It is used with the WASP III Plus power system planning package developed by IAEA to evaluate long term investment decisions. The use of hydro energy generation values from this research methodology in the long term expansion planning studies gives a more cost effective expansion plan. The new plan shows a reduction in the total discounted cost, system operation costs and the total installed capacity required to meet the load growth over the period of twenty years. |
| Year | 1998 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. WM-97-01 |
| Type | Dissertation |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Gupta, Ashim Das; |
| Examination Committee(s) | Shrestha, Ram M. ;Nattawuth Udayasen ;Kindler, Janusz; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1998 |