Impacts of Wind Power Integration on Generation Dispatch in Power Systems

Jae-Kun Lyu,Jae-Haeng Heo,Mun-Kyeom Kim,Jong-Keun Park 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

The probabilistic nature of renewable energy, especially wind energy, increases the needs for new forms of planning and operating with electrical power. This paper presents a novel approach for determining the short-term generation schedule for optimal operations of wind energy-integrated power systems. The proposed probabilistic security-constrained optimal power flow (P-SCOPF) considers dispatch, network, and security constraints in pre- and post-contingency states. The method considers two sources of uncertainty: power demand and wind speed. The power demand is assumed to follow a normal distribution, while the correlated wind speed is modeled by the Weibull distribution. A Monte Carlo simulation is used to choose input variables of power demand and wind speed from their probability distribution functions. Then, P-SCOPF can be applied to the input variables. This approach was tested on a modified IEEE 30-bus system with two wind farms. The results show that the proposed approach provides information on power system economics, security, and environmental parameters to enable better decision-making by system operators.

Security Cost Analysis with Linear Ramp Model using Contingency Constrained Optimal Power Flow

Jae-kun Lyu,Mun-Kyeom Kim,Jong-Keun Park 대한전기학회 2009 Journal of Electrical Engineering & Technology Vol.4 No.3

This paper proposes a novel technique for calculating the security costs that properly includes ramping constraints in the operation of a deregulated power system. The ramping process is modeled by a piecewise linear function with certain assumptions. During this process, a ramping cost is incurred if the permissible limits are exceeded. The optimal production costs of the power producers are calculated with the ramping cost included, considering a time horizon with N-1 contingency cases using contingency constrained optimal power flow (CCOPF), which is solved by the primal-dual interior point method (PDIPM). A contingency analysis is also performed taking into account the severity index of transmission line outages and its sensitivity analysis. The results from an illustrative case study based on the IEEE 30-bus system are analyzed. One attractive feature of the proposed approach is that an optimal solution is more realistic than the conventional approach because it satisfies physical constraints, such as the ramping constraint.

Security Cost Analysis with Linear Ramp Model using Contingency Constrained Optimal Power Flow

Lyu, Jae-kun,Kim, Mun-Kyeom,Park, Jong-Keun The Korean Institute of Electrical Engineers 2009 Journal of Electrical Engineering & Technology Vol.4 No.3

This paper proposes a novel technique for calculating the security costs that properly includes ramping constraints in the operation of a deregulated power system. The ramping process is modeled by a piecewise linear function with certain assumptions. During this process, a ramping cost is incurred if the permissible limits are exceeded. The optimal production costs of the power producers are calculated with the ramping cost included, considering a time horizon with N-1 contingency cases using contingency constrained optimal power flow (CCOPF), which is solved by the primal-dual interior point method (PDIPM). A contingency analysis is also performed taking into account the severity index of transmission line outages and its sensitivity analysis. The results from an illustrative case study based on the IEEE 30-bus system are analyzed. One attractive feature of the proposed approach is that an optimal solution is more realistic than the conventional approach because it satisfies physical constraints, such as the ramping constraint.

Impacts of Wind Power Integration on Generation Dispatch in Power Systems

Lyu, Jae-Kun,Heo, Jae-Haeng,Kim, Mun-Kyeom,Park, Jong-Keun The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

The probabilistic nature of renewable energy, especially wind energy, increases the needs for new forms of planning and operating with electrical power. This paper presents a novel approach for determining the short-term generation schedule for optimal operations of wind energy-integrated power systems. The proposed probabilistic security-constrained optimal power flow (P-SCOPF) considers dispatch, network, and security constraints in pre- and post-contingency states. The method considers two sources of uncertainty: power demand and wind speed. The power demand is assumed to follow a normal distribution, while the correlated wind speed is modeled by the Weibull distribution. A Monte Carlo simulation is used to choose input variables of power demand and wind speed from their probability distribution functions. Then, P-SCOPF can be applied to the input variables. This approach was tested on a modified IEEE 30-bus system with two wind farms. The results show that the proposed approach provides information on power system economics, security, and environmental parameters to enable better decision-making by system operators.

풍력발전의 변동성을 고려한 기동정지계획에서의 적정 Ramping 용량 산정

류재근(Jae-Kun Lyu),허재행(Jae-Haeng Heo),박종근(Jong-Keun Park) 대한전기학회 2013 전기학회논문지 Vol.62 No.4

Wind energy is rapidly becoming significant generating technologies in electricity markets. As probabilistic nature of wind energy creates many uncertainties in the short-term scheduling, additional actions for reliable market operation should be taken. This paper presents a novel approach to evaluate ramping capability requirement for changes in imbalance energy between day-ahead market and real-time market due to uncertainty of wind generation as well as system load. Dynamic ramp rate model has been applied for realistic solution in unit commitment problem, which is implemented in day-ahead market. Probabilistic optimal power flow has been used to verify ramping capability determined by the proposed method is reasonable in economic and reliable aspects. This approach was tested on six-bus system and IEEE 118-bus system with a wind farm. The results show that the proposed approach provides ramping capability information to meet both forecasted variability and desired confidence level of anticipated uncertainty.

풍력발전이 포함된 전력시장에서의 출력 변동성 감소를 위한 Ramping Capability 확보에 관한 연구

류재근(Jae-Kun Lyu),허재행(Jae-Haeng Heo),박종근(Jong-Keun Park) 대한전기학회 2012 대한전기학회 학술대회 논문집 Vol.2012 No.10

Maintenance Priority Index of Overhead Transmission Lines for Reliability Centered Approach

Jae-Haeng Heo,Mun-Kyeom Kim,Dam Kim,Jae-Kun Lyu,Yong-Cheol Kang,Jong-Keun Park 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

Overhead transmission lines are crucial components in power transmission systems. Welldesigned maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

Three-dimensional Macropore Arrays in p-type Silicon Fabricated by Electrochemical Etching

Jae Hyun Kim,Kang-Pil Kim,Hong-Kun Lyu,Sung-Ho Woo,Hong-Seok Seo,Jung-Ho Lee 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.1

Ordered macropores formed in p-type silicon substrates (10~20Ω·cm) by using electrochemical anodization in various HF-containing electrolytes was investigated under different operating conditions. The effect of electrolyte composition and etch pits on controlling the formation of macropores on periodically arranged pores is reported. The results revealed that the natures of the constituents of the solution play very important roles in determining pore formation and morphology and that stable ordered macropore growth is not possible without an inverse pyramid notch. By using a Si/SiGe/Si/SiGe/p-type silicon structure, we were able to fabricate ordered pillar structures without an etch pit formation process. A possible role of two sets of Si/SiGe layers in pillar formation is proposed. Ordered macropores formed in p-type silicon substrates (10~20Ω·cm) by using electrochemical anodization in various HF-containing electrolytes was investigated under different operating conditions. The effect of electrolyte composition and etch pits on controlling the formation of macropores on periodically arranged pores is reported. The results revealed that the natures of the constituents of the solution play very important roles in determining pore formation and morphology and that stable ordered macropore growth is not possible without an inverse pyramid notch. By using a Si/SiGe/Si/SiGe/p-type silicon structure, we were able to fabricate ordered pillar structures without an etch pit formation process. A possible role of two sets of Si/SiGe layers in pillar formation is proposed.

Application of Particle Swarm Optimization to the Reliability Centered Maintenance Method for Transmission Systems

Jae-Haeng Heo,Jae-Kun Lyu,Mun-Kyeom Kim,Jong-Keun Park 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.

Application of Particle Swarm Optimization to the Reliability Centered Maintenance Method for Transmission Systems

Heo, Jae-Haeng,Lyu, Jae-Kun,Kim, Mun-Kyeom,Park, Jong-Keun The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.