Demand Side Management in Small Power Systems – The Estonian Case Study

The increasing amount of stochastic power generation connected to power system increases the need for additional ancillary reserves. Most of today's electricity consumers are relatively flexible and easily controllable,providing an already existing supplement for traditional power system ancillary services. The flexibility of loads depends on the number, type and size of consumers. In small power systems utilizing loads for power system services pose different challenges for the system operator than in larger systems. The main challenge lies in developing a business case and incentives for the customers to participate in such services. This paper discusses and analyses the Estonian three most energy intensive economic sectors potential for demand side response from a small power system point of view. Generally, it is determined that demand side flexibility provides incentives not only for the power system operator but also for the customer who is able optimize its processes to gain higher economic and energy efficiency and at the same time provide flexibility for the system operator

Benchmarking of Power Quality Performance in Transmission Systems – CIGRE WG C4.27 Perspective

This paper describes the activities of CIGRE WG C4.27 Benchmarking of Power Quality Performance in Transmission Systems . The WG was established in December 2012 in recognition of demand for coherent set of guidelines for benchmarking power quality performance in existing and future transmission networks. During the work the members of the WG have compiled extensive material related to the state of the art of benchmarking power quality performance in transmission systems. This paper summarizes current understanding of benchmarking power quality performance issues and identifies directions in which the WG will continue to work in order to provide resolutions to outstanding questions

Assessment of corona loss performance on aging transmission lines using PMU measurements

This paper presents an assessment of corona loss performance for two overhead transmission lines of different ages using synchronized phasor measurements. In general, it is believed that the aged overhead transmission lines have constrained performance compared to the newer ones as they have been exposed to different environmental conditions for longer period of time. Therefore, in view of availability of synchronized measurements it is possible and of relevance to assess how the corona losses are influenced by line age and what are the main influencing factors. The results of the analysis indicate that there are higher corona losses associated with older overhead transmission lines and respective information is directly applicable for transmission system operators in their system operational planning in order to optimize the purchase of losses from the market

Verification of a Wind Farm Aggregated Generic Dynamic Model Based on a Real Fault Ride-Through Test in the Grid

Full power converter wind turbines are believed to have better grid fault responses compared to other types of wind turbines. However, validation of this model with field measurement data is rarely reported in papers. This paper is aimed at validating a dynamic model of a wind farm consisting of full power converter wind turbines against field measurements recorded at Estonian power system

Experiences with Steady-State PMU Compliance Testing using Standard Relay Testing Equipment

This paper presents the results of steady state compliance testing of phasor measurement units (PMUs) from three different vendors in a laboratory environment. Testing is performed by providing three phase voltage and current injections to the VT and CT inputs of the PMUs through Freja-300 stand-alone protection relay test set. Testing is performed according to the standard “IEEE C37.242-2013 - IEEE Guide for Synchronization, Calibration, Testing, and Installation of Phasor Measurement Units (PMUs) for Power System Protection and Control”. The paper discusses the test setup, testing process and overall test results of this project. The limitations of stand-alone testing equipment and recommendations for utilizing real-time hardware-in-the-loop simulation for thorough testing of PMUs are also presented. QC 20141208</p

Estimation of Power System Inertia From Ambient Wide Area Measurements

This study presents a method of estimating the effective inertia of a power system from ambient frequency and active power signals measured by phasor measurement units. Most importantly, we demonstrate that inertia can be estimated from ambient measurement data, not only from disturbances. This leads to the possibility of monitoring inertia in a close to continuous manner in the time scale of minutes or tens of minutes. The method allows the system to be divided into a number of areas and the effective inertia of each area to be estimated as a separate quantity. In principle, inertia is estimated by observing the dynamics between changes in active power and resulting frequency deviations during normal operation of the system. The method is based on applying system identification on these measurements and extracting inertia values from identified models. Efficacy of the method is demonstrated on results of real measurements from the Icelandic power system