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| 08-04 | Initial Review of Methods for Cascading Failure Analysis in Electric Power Transmission Systems
Large blackouts are typically caused by cascading
failure propagating through a power system by means of a
variety of processes. Because of the wide range of time scales,
multiple interacting processes, and the huge number of possible
interactions, the simulation and analysis of cascading blackouts
is extremely complicated. This paper defines cascading failure for
blackouts and gives an initial review of the current understanding,
industrial tools, and the challenges and emerging methods
of analysis and simulation.
IEEE PES General Meeting, July 2008. Uploaded: February 22, 2008. | IEEE PES CAMS Task Force on Cascading Failures | 4/11/2008 | 121.6k | PDF |
| 08-08 | Control of Inverter-Connected Sources in Autonomous Microgrids
Abstract-The use of distributed generation is growing steadily, motivating a need for flexible interconnection strategies. The resulting microgrid concept allows sub-networks of sources and loads to maintain reliable operation when disconnected from the main grid. The paper presents a control strategy for inverter-based sources that supports transitioning between grid connection and autonomous operation. The controller regulates the inverter terminal voltage and the active power delivered to the AC system, and takes into account the phase-locked loop (PLL) dynamics. An example, in which two SOFC plants provide power to a microgrid, explores controller behaviour. The investigation considers disconnection from the main grid, autonomous operation, and re-synchronization with the main grid.
I.A. Hiskens and E.M. Fleming, "Control of Inverter-Connected Sources in Autonomous Microgrids," to appear in the Proceedings of the American Control Conference, Seattle, WA, June 2008.
Uploaded: April 17, 2008 | Ian A. Hiskens, Eric M. Fleming | 5/7/2008 | 1.3M | PDF |
| 08-09 | Optimal Transmission Switching with Contingency Analysis
Abstract-In this paper, we continue to analyze optimal dispatch of generation and transmission topology to meet load as a mixed integer program (MIP) with binary variables representing the state of the transmission element (line or transformer). Previous research showed a 25%
savings by dispatching the IEEE 118-bus test case with a DCOPF. This paper is an extension of that work by examining the effects of transmission switching with an N-1 DCOPF on the IEEE 118-bus and the IEEE 73-bus test case, also known as the RTS 96 system. We demonstrate that these networks can be operated to satisfy N-1 standards while cutting costs by incorporating transmission switching into the dispatch. In some cases, the percent savings from transmission switching was higher with an N-1 DCOPF formulation than with a DCOPF formulation. We also analyze both IEEE test cases at varying load levels.
PSERC unpublished working paper
Uploaded: April 17, 2008 | Shmuel Oren, Kory Hedman, Richard O'Neill, Bartholomew Fisher | 5/7/2008 | 320.9k | PDF |
| 08-10 | Optimal Transmission Switching - Sensitivity Analysis and Extensions
Abstract-In this paper, we continue to analyze optimal dispatch of generation and transmission topology to meet load as a mixed integer program (MIP) with binary variables representing the state of the transmission element (line or transformer). Previous research showed a 25% savings by dispatching the IEEE 118-bus test case. This paper is an extension of that work. It presents how changing the topology affects nodal prices, load payment, generation revenues, cost, and rents, congestion rents, and flowgate prices. Results indicate that changing the topology to cut costs typically results in lower load payments and higher generation rents for this network. Computational issues are also discussed.
PSERC unpublished working paper
Uploaded: April 17, 2008 | Shmuel Oren, Kory Hedman, Richard O'Neill, Bartholomew Fisher | 5/7/2008 | 329.3k | PDF |
| 08-11 | VaR Constrained Hedging of Fixed Price Load-Following Obligations in Competitive Electricity Markets
Abstract-Load serving entities providing electricity to regulated customers have an obligation to serve load that is subject to systematic and random fluctuations at fixed prices. In some jurisdictions like New Jersey, such obligations are auctioned off annually to third parties that commit to serve a fixed percentage of the fluctuating load at a fixed energy price. In either case the entity holding the load following obligation is exposed to the load variation and to a volatile wholesale spot market price which is correlated with the load level. Such double exposure to price and volume results in a net revenue exposure that is quadratic in price and cannot be adequately hedged with simple forward contracts whose payoff is linear in price. A fixed quantity forward contract cover, is likely to be short when the spot price is high and long when the spot price is low.
In this paper we develop a self-financed hedging portfolio consisting of a risk free bond, a forward contract, and a spectrum of call and put options with different strike prices. A popular portfolio design criterion is the maximization of expected hedged profits subject to a value at risk (VaR) constraint. Unfortunately, that criteria is difficult to implement directly due to the complicated form of the VaR constraint. We show, however, that under plausible distributional assumptions, the optimal VaR contrained portfolio is on the efficient Mean-Variance frontier. Hence, we propose an approximation method that restricts the search for the optimal VaR constrained portfolio to that efficient frontier. The proposed approach is particularly attractive when the Mean-Variance efficient frontier can be represented analytically, as is the case, when the load and logarithm of price follow a bivariate normal distribution. We illustrate the results with a numerical example.
PSERC unpublished working paper
Uploaded: April 17, 2008 | Yumi Oum, Shmuel Oren | 5/7/2008 | 291.8k | PDF |
| 08-13 | Estimating Wind Turbine Parameters and Quantifying Their Effects on Dynamic Behavior (S-34)
Abstract-Numerous models have been proposed for representing variable-speed wind turbines in grid stability studies. Often the values for model parameters are poorly known though. The paper initially uses trajectory sensitivities to quantify the effects of individual parameters on the dynamic behavior of wind turbine generators. A parameter estimating process is then used to deduce parameter values from disturbance measurements. Issues of estimation bias arising from non-identifiable parameters are considered. The paper explores the connection between the type of disturbance and the parameters that can be identified from corresponding measurements. This information is valuable in determining the measurements that are required from testing procedures and disturbances in order to build a trustworthy model.
Uploaded: June 9, 2008. | Ian Hiskens, Jonathon Rose | 6/9/2008 | 457.2k | PDF |
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