Low-frequency oscillations may cause unstable operation of power system. It is so very important that the operator is alerted in time and provided with sufficient amount of information. In the paper a method for monitoring and risk assessment of low-frequency oscillations in the system is described which allows integration with other similar tools. We also proposed a model for reporting of the results to the operator in a proper way. The method has been tested on a model of the real power system.
COBISS.SI-ID: 7850068
The risk that arises from sales contract offer maturity can reduce or even neutralize the retailer’s profit on the retail electricity market. To develop a mitigation strategy for this risk, a retailer clearly needs a model for a detailed risk analysis. This paper presents a fundamental model for evaluating this risk and a methodology for its use, and compares its analytical performance with traditional techniques obtained from the option-pricing theory. A realistic example illustrates the use and the benefits of the proposed model in risk analysis of the electricity retail business.
COBISS.SI-ID: 7220820
A theory of a power system response to an appearance of active power deficit is given in the paper. An argumentation is given why the Center Of Inertia COI frequency is the only relevant signal for an underfrequency load shedding UFLS protection. A modification of an adaptive UFLS scheme is given. By monitoring the first frequency derivative of COI it is possible to modify the amount of load shedding at each shedding step. In this way the total load shedding amount can be significantly decreased. A comparison of this modified scheme with a theoretically optimal UFLS approach is given.
COBISS.SI-ID: 7855188
Voltage fluctuations in transmission networks caused by the operations of large consumers, for example, electric arc furnaces, are often the primary sources of high levels of flicker at the end-users. This article compares two methods for simulating the flicker propagation in a meshed high voltage network by comparing simulated levels of flicker with levels obtained from field measurements. The comparison of the simulated and measured flicker values was extended to include two different network schemes and provides a further insight into the nature of flicker propagation in power networks.
COBISS.SI-ID: 7834196
In the paper, Markov chains in conjunction with Monte Carlo simulation are used to predict the power system security level. The new, fast and efficient method uses a Markov chain for each identified security range to track the development of security level through time, based on the forecasted and recorded data. The method has been tested on the Bosnian test power system using the recorded data on security levels during one year period. The forecasted results show a striking coincidence with the real security levels. The presented method could be incorporated in WAMS in control centers.
COBISS.SI-ID: 6879572