Richard G. Farmer

Economic impact analysis of load forecasting

This paper examines the economic impact of inaccurate load forecasts. Monte Carlo simulations are used to study the effect of different load forecasting accuracy. Investigations into the effect of improving the daily peak load forecasts, effect of different seasons of the year and effect of utilization factors are also presented.

Dynamic voltage compensation on distribution feeders using flywheel energy storage

Advancements in power electronics, bearings and materials have made flywheel energy storage systems a viable alternative to electrochemical batteries. A future application of such a device is as an uninterruptible power supply for critical loads on a distribution feeder. However, the same power electronics and flywheel system could also be used for dynamic voltage compensation. A comparison is made between series and parallel connection of such dynamic compensation techniques used to maintain rated load voltage on distribution feeders when there are momentary dips in the supply voltage. For each case a mathematical model is presented and analyzed. The two cases are compared and the series compensation technique is more effective.

A combined uninterruptible power supply and dynamic voltage compensator using a flywheel energy storage system

Due to technological advancements, the flywheel energy storage system is becoming a viable alternative to electrochemical batteries. Two potential applications of flywheel systems are for voltage support and as an uninterruptible power supply. The two applications are both useful to protect critical loads on distribution feeders. Therefore, it may be useful to look at the possibility of combining both functions into one system. This paper considers a flywheel energy storage system which performs both functions and presents a novel control scheme using both sinusoidal pulse width modulation as well as a boost converter to regulate the critical load voltage on the feeder. Dynamic voltage compensation is achieved by injecting voltage through series transformers rather than by connecting the system in shunt, to minimize the amount of kVA required by the flywheel system. Simulations are provided using the Electromagnetic Transients Program to validate the concept.

Effect of probabilistic inputs on neural network-based electric load forecasting

This paper presents a novel method to include the uncertainties or the weather-related input variables in neural network-based electric load forecasting models. The new method consists of traditionally trained neural networks and a set of equations to calculate the mean value and confidence intervals of the forecasted load. This method was tested for daily peak load forecasts for one year by using modified data from a large power system. The tests indicate that in addition to the confidence interval, the new method provides a more accurate mean forecast than a multilayer perceptron networks alone.

Estimation of unscheduled flows and contribution factors based on L/sub p/ norms

This paper portrays a novel approach based on L/sub p/ norms to estimate the unscheduled flows occurring in a wide area interconnected system. Contribution factors for the utilities toward the loop flow scenario are designed based on the participation. This may be used as an effective market tool to establish equitable charge or compensation to utilities.

Estimation of generator excitation-system parameters by tabu search

The paper presents a tabu search method for estimating the parameters of a generator excitation-system model. To apply the method, it is necessary to have a measured time domain response of the generator and excitation system for a specific perturbation. The method systematically compares the measured response to simulated responses using different sets of excitation system parameters. This comparison continues until it has been determined that a set of parameters has been identified that gives the best comparison between the measured response and the simulated response. An algorithm for the tabu search has been developed, which provides quick convergence and a satisfactory solution. This algorithm has been applied for a generator and excitation system that has been field-tested. The paper shows that a set of parameters has been found by the tabu search method, which provides excellent comparison of the simulated response to the measured response.

Real-time analysis of transient stability using reconfigurable analog VLSI

This letter presents a new method to perform transient stability analysis of a system using reconfigurable analog VLSI. A novel concept for reconfiguring system parameters has been developed and tested using a one generator infinite bus system.

Z-Bus Based Frequency Scanning Program for Sub-Synchronous Resonance Screening

The paper presents the development of a frequency scanning program used for subsynchronous resonance (SSR) screening. The developed program is capable of screening power systems with hundreds of buses. The heart of the program is Z- Bus (Bus Impedance Matrix) of the power system as a function of frequency. The paper describes a fast and efficient method for forming Z-bus. The paper includes validation of the developed program by comparing case results with the IEEE Second Benchmark Model. Frequency scanning results from the application of the program to an existing power system are presented.

A flow-based approach for evaluating fuel cell interconnections to a distribution feeder

A combined flow-based and a marginal cost approach for identifying and quantifying costs-benefits for distributed generators is presented in this paper. The proposed methodology quantifies the interconnection benefits from a distributed generator in terms of total avoided costs. A fuel cell distributed generator is considered for the analysis and for describing the methodology. The transfer distribution factors (TDFs) which depend on the network topology for a given power network are used to quantify the locational benefits. These TDFs are used to calculate the incremental flow changes due to the distributed generator. The marginal capacity and energy costs are used to quantify the avoided costs due to deferred capacity expansion benefits, avoided energy costs and avoided transmission/distribution losses. The approach could also be used to compare and contrast different interconnection points for a fuel cell from a cost-benefit stand point for a utility.