Pranavamoorthy Balasubramanian

Real-Time Contingency Analysis With Transmission Switching on Real Power System Data

Transmission switching (TS) has shown to be an effective power flow control tool. TS can reduce the system cost, improve system reliability, and enhance the management of intermittent renewable resources. This letter addresses the state-of-the-art problem of TS by developing an AC-based real-time contingency analysis (RTCA) package with TS. The package is tested on real power system data, taken from energy management systems of PJM, TVA, and ERCOT. The results show that post-contingency corrective switching is a ready to be implemented transformational technology that provides substantial reliability gains. The computational time and the performance of the developed RTCA package, reported in this letter, are promising.

Real-Time Corrective Switching in Response to Simultaneous Contingencies

AbstractThe standard optimal power flow (OPF) problem is an economic dispatch (ED) problem combined with transmission constraints, which are based on a static topology. Prior research has demonstrated that cooptimization of generation dispatch and transmission topology results in cost savings. However, the computational complexity associated with topology control (TC) has been a major deterrent to its implementation. The proposed work investigates the application of a heuristic, a greedy algorithm, to improve the computational time for the TC problem while still maintaining the ability to find quality solutions. An expression is derived, which indicates the impact on the objective for a marginal change in the state of a transmission line. This expression is used to generate a priority list with potential candidate lines for switching, which may provide huge improvements to the system. The advantage of this method is that it is a fast heuristic as compared to using mixed integer programming (MIP) to find a...

Harnessing Flexible Transmission: Corrective Transmission Switching for ISO-NE

Despite the significant attention transmission switching (TS) has gained over the last decade, important challenges remain. This paper addresses the state-of-the-art challenges of TS by studying the benefits of corrective switching using authentic Independent System Operator of New England (ISO-NE) data and software. Thus, the results and analyses presented in this paper are more convincing than any other study conducted to date. TS is successfully implemented for reliability applications as a corrective mechanism. ISO-NE maintains N -1 reliability based on the preventive dispatch and enforcing proxy reserve requirements along with N - 1 - 1 reliability based on reserves and interface limits. This paper incorporates TS as a corrective mechanism in response to both the N - 1 and N - 1 - 1 events. Not only does this paper investigate the capability of corrective switching to alleviate thermal overloads but also the economic benefits of corrective switching with actual market data and in-house market software at ISO-NE. The results show that corrective TS can improve the reliability of the system and save millions of dollars each year by providing a cheaper corrective action alternative for ISO-NE. The results also suggest that TS would provide more significant benefits for systems with more transmission congestion such as Pennsylvania New Jersey Maryland, Midcontinent Independent System Operator, and Electric Reliability Council of Texas.

Real-Time Contingency Analysis With Corrective Transmission Switching

Transmission switching (TS) has gained significant attention recently. However, barriers still remain and must be overcome before the technology can be adopted by the industry. The state-of-the-art challenges include AC feasibility, computational complexity, the ability to handle large-scale real power systems, and dynamic stability. This paper investigates these challenges by developing an AC corrective TS (CTS) based real-time contingency analysis (RTCA) tool that can handle large-scale systems within a reasonable time. The tool quickly proposes multiple high-quality corrective switching actions for contingencies with potential violations. To reduce the computational complexity, three heuristic algorithms are proposed to generate a small set of candidate switching actions. Parallel computing is implemented to further speed up the solution time. Moreover, time-domain simulations are performed to check for dynamic stability of the proposed CTS solutions. The promising results, tested on the Tennessee Valley Authority (TVA) system and actual energy management system snapshots from the PJM Interconnection (PJM) and the Electric Reliability Council of Texas (ERCOT), show that the tool effectively reduces post-contingency violations. It is concluded that CTS is ripe for industry adoption for RTCA application.

Market Implications of Wind Reserve Margin

The level of uncertainty, which the power system operators should account for, increases as more renewables are integrated in the system. Additional operating reserves needs to be scheduled within security constrained economic dispatch to ensure reliability. Existing practices rely on conventional generators for providing operational flexibility required to mitigate the uncertainty introduced by renewables. However, with the increased share of renewables in the generation mix, such intermittent resources would be expected to take part in the balancing tasks, too. Providing a reserve margin allows wind generators to hedge against uncertainty. This paper examines the market implications of wind reserve margin policies used to mitigate uncertainty from wind resources. The market implications of the recently proposed optimized reserve margin policy factors are studied. Analysis on the Reliability Test System 1996 shows that reserve margin policy factors along with the proposed compensation scheme help in allocating payments toward renewable resources that present a good quality of service.

A data-driven heuristic for corrective transmission switching

Utilizing flexibility of the transmission network has gained significant attention recently. Prior efforts have shown that various benefits could be achieved by appropriately changing the network topology. This paper focuses on the reliability gains that can be achieved through corrective transmission switching (CTS). A full AC contingency analysis is conducted to identify critical contingencies that would result in violations. CTS is employed on these critical contingencies to test for violation reductions. A data-driven heuristic is proposed in this paper to identify the candidate switching list. This heuristic, also referred to as enhanced data mining (EDM) approach, provides a static lookup table consisting of corrective switching solutions, which is fast and effective. The lookup table can be created through a straightforward data mining technique. Simulations on the TVA system demonstrate the effectiveness and efficiency of the proposed heuristic.