A risk evaluation method for ramping capability shortage in power systems

2017

This paper proposes an index called net load carrying capability (NLCC) to evaluate the contribution of a generating unit to the flexibility of a power system. NLCC is defined as the amount by which the load can be increased when a generating unit is added to the system, while still maintaining the flexibility of the system. This index is based on the flexibility index termed ramping capability shortage expectation (RSE), which has been used to quantify the risk associated with system flexibility. This paper argues that NLCC is more effective than effective load carrying capability (ELCC) in quantifying the contribution of the generating unit to flexibility. This is explained using an illustrative example. A case study has been performed with a modified IEEE-RTS-96 to confirm the applicability of the NLCC index. The simulation results demonstrate the effect of operating conditions such as operating point and ramp rate on NLCC, and show which kind of unit is more helpful in terms of flexibility.

Section: Net Load Carrying Capabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Net Load Carrying Capability of Generating Units in Power Systems

2017

“…The latter is useful for reducing the computational time in large power systems. Please refer to [22] for further information on the RSE.…”

Section: Flexibility Index: Ramping Capability Shortage Expectationmentioning

confidence: 99%

“…In this paper, a flexibility index, RSE, is used to capture the flexibility of the power system. The RSE calculation process is described as follows [22].…”

Section: Flexibility Index: Ramping Capability Shortage Expectationmentioning

confidence: 99%

Flexibility-Based Reserve Scheduling of Pumped Hydroelectric Energy Storage in Korea

2017

Abstract:The high penetration of renewable energy resources has made it harder to secure a flexible power system. Accordingly, this has become an issue in operating power systems. As a possible solution, pumped hydroelectric energy storage (PHES) has received much attention because of its fast start-up and ramp characteristics. This study proposes a flexibility-based reserve scheduling method for PHES. In this method, the reserve scheduling of PHES was conducted to improve flexibility; the associated risk index was termed the ramping capability shortage expectation (RSE). The peak-load days in 2016 and 2029 were selected to examine the applicability and performance of the proposed method. Results indicate that the proposed method can improve the flexibility by 4.45% for 2016 and 0.9% for 2029, respectively.

“…In the process of introducing VG into the power grid, many studies have demonstrated the lack of flexibility in the operation and planning of the system because unexpected variations in VG would lead to a power mismatch [4][5][6][7][8]. Flexibility is generally defined as the ability to respond to changes in net load (i.e., load minus VG).…”

Section: Introductionmentioning

confidence: 99%

Flexibility-Based Evaluation of Variable Generation Acceptability in Korean Power System

2017

This study proposes an evaluation method for variable generation (VG) acceptability with an adequate level of power system flexibility. In this method, a risk index referred to as the ramping capability shortage expectation (RSE) is used to quantify flexibility. The RSE value of the current power system is selected as the adequate level of flexibility (i.e., RSE criterion). VG acceptability is represented by the VG penetration level for the RSE criterion. The proposed evaluation method was applied to the generation expansion plan in Korea for 2029 in order to examine the validity of the existing plan for VG penetration. Sensitivity analysis was also performed to analyze the effects of changes in system uncertainty on VG acceptability. The results show that the planned VG penetration level for 2029 can improve by approximately 12% while securing flexibility.