Zeliang Ma

Life Cycle Cost estimate of power system planning

In this paper, a two-dimensional Life Cycle Cost (LCC) model of power system planning as a whole is established in order to overcome the defect that the applications of LCC are traditionally limited to specific equipment or phase. The previous researches of LCC technology are reviewed. The cost breakdown structure is described in detail particularly from the device layer and the system layer. The maintenance costs combining with Reliability Centered Maintenance (RCM) and the failure costs combining with outage costs are analyzed significantly. Using this model, LCC estimate of two alternatives for transmission section of 500kV power system planning in East China Power Grid is implemented, during which the data management system, the LCC calculation results, the sensitivity analysis and the applications are all considered. The case results verify the feasibility and validity of this LCC model. The proposed approach provides a new idea and effective way to enhance the cost management business for the enterprises in the future.

Investigation on Limit Surfaces in Space Spanned by Generation Parameter

In a space spanned by generation parameter, the different properties of loading margin surface and generation limit surface are investigated at first in this paper. Then, the shortage of taking the generation limit surface as limit boundary for generation rescheduling (GR) is elaborated and a developed GR model is presented. Additionally, in order to take the uncertainty of load pattern into consideration, a bilevel programming model with the opposite structure to each other is proposed. In this model, the upper level is used to optimize generation pattern (GP) for maximizing the loading margin while the lower level is used to determine the worst load pattern for checking the adaptability of the GP to the variation of the load pattern. A Step-by-step Approximation based Primal Dual Interior Point method (SAPDIP method) and Successive Linear Programming method (SLP method) are used to solve the two sub-models, respectively. The GP optimized by the proposed model reflects the balance between the “variation” and “adaption”, and is less sensitive to the changes in load pattern. Finally, the proposed method is tested on multiple standard IEEE test systems as well as a real power system in China.

Transmission surplus capacity based power transmission expansion planning using Chaos optimization Algorithm

A novel power transmission expansion planning model and its application algorithm which considers the transmission surplus capacity and load factor of the transmission line is presented. In traditional transmission expansion planning, some transmission lines will run at a high load factor due to ignore the load level of transmission lines. This may lead to congestion in network and degrade dispatch flexibility. Such a planning process has put more emphasis on investment optimization than other aspects. This paper describes new objectives which aim to get the best distribution of branch load factors together with minimizing the investment simultaneously. Chaos Optimal Algorithm (COA) is introduced and used to solve transmission expansion planning problem due to its stochastic and ergodic characteristics. Its effectiveness of the proposed model and methodology are tested in two typical systems.

Impacts of an UHVDC Transmission Link on Operation Security and Stability of East China Power Grid

The first ±800kV UHVDC transmission system is connected with the East China power grid around 2010 and its maximum transfer capacity will reach to 6.4GW. It brings new challenges and impacts on the network structure, operation security and reliability and system stability. In the paper, East China power gird configuration and load level for 2012 is adopted as base case for study. The power system simulation tools, such as PSS/E、BPA, etc, are used to study the system security and reliability under conditions of typical UHVDC operation modes. Technical issues associated with impacts of the ±800kV UHVDC connection on voltage stability, power transfer capability (ATC), system reliability are particularly studied. Some useful conclusions and suggestions for transmission system planning, operation security and stability considering the UHVDC connection are drawn in the end.

Reactive power optimization and control considering penetration reactive power for ultra-high voltage power system

With the development of UHV (Ultra-High Voltage) transmission, great changes have occurred for the reactive power distribution. Especially the reactive power of UHV transmission varies with the different transmission power. Therefore, reactive power optimization considering penetration reactive power is presented in this paper. The estimation of the penetration reactive power is proposed in the paper. The optimization scheme can minimize the penetration reactive power of the UHV transmission and hence the voltage stability margin of the whole power system with UHV transmission. And the optimization is solved based on improved differential evolution algorithm. An example of Huadong power grid is discussed and analyzed. And its proved that the present optimization control is effective and pratical.