Power quality and electromagnetic compatibility: special report, session 2

The scope of Session 2 (S2) has been defined as follows by the Session Advisory Group and the Technical Committee: Power Quality (PQ), with the more general concept of electromagnetic compatibility (EMC) and with some related safety problems in electricity distribution systems. Special focus is put on voltage continuity (supply reliability, problem of outages) and voltage quality (voltage level, flicker, unbalance, harmonics). This session will also look at electromagnetic compatibility (mains frequency to 150 kHz), electromagnetic interferences and electric and magnetic fields issues. Also addressed in this session are electrical safety and immunity concerns (lightning issues, step, touch and transferred voltages). The aim of this special report is to present a synthesis of the present concerns in PQ&EMC, based on all selected papers of session 2 and related papers from other sessions, (152 papers in total). The report is divided in the following 4 blocks: Block 1: Electric and Magnetic Fields, EMC, Earthing systems Block 2: Harmonics Block 3: Voltage Variation Block 4: Power Quality Monitoring Two Round Tables will be organised: - Power quality and EMC in the Future Grid (CIGRE/CIRED WG C4.24, RT 13) - Reliability Benchmarking - why we should do it? What should be done in future? (RT 15

Compound index for power quality evaluation and benchmarking

High level of delivered power quality (PQ) is becoming one of the key performance indicators for both contemporary and future power networks. The increased proliferation of converter connected generation and load in power networks, increased sensitivity to network disturbances of some of these new types of devices and requirements for more flexible operation of power networks led to the revision of some of PQ standards and introduction of modified or in some cases new requirements for PQ compliance. Although almost all PQ phenomena, with exception of voltage transients, are well defined and appropriate thresholds for individual phenomena are set in international standards, there is no standardised nor commonly accepted way to describe and evaluate the overall PQ performance at buses. This study presents an analytic hierarchy process (AHP) inspired methodology for assessing the overall PQ performance at a bus based on several different PQ phenomena considered simultaneously. Compound bus PQ index is defined using AHP to present the overall PQ performance at the bus with respect to voltage sag, harmonics and voltage unbalance. The application of the methodology is illustrated on a 295 bus generic distribution network

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

3-Phase 4-wire matrix converter-based voltage sag/ swell generator to test low-voltage ride through in wind energy conversion systems

The high penetration of energy from wind energy conversion systems (WECSs) can have a significant influence on the stability, power quality and reliability of power systems. Therefore several countries have developed stringent grid codes in recent years in order to enhance the overall stability of power systems. In these grid codes, the capacity to fulfil low-voltage ride through (LVRT) requirements is considered an important issue for the control of WECSs. Therefore in this study, a novel voltage sag/ swell generator (VSG) based on a 4-leg matrix converter is presented. This VSG can be used to generate the symmetrical and asymmetrical faults required to test LVRT algorithms in a laboratory environment. The performance of the VSG is experimentally demonstrated and compared with the operation of other VSGs conventionally used for LVRT studies

Techno-economic analysis of global power quality mitigation strategy for provision of differentiated quality of supply

This paper presents a comprehensive methodology for techno-economic assessment of power quality (PQ) mitigation solutions, both network-based and device-based, and proposes an optimisation-based PQ mitigation strategy for delivering differentiated PQ in networks integrated with renewable generation. The proposed strategy is based on the evaluation of financial losses due to several critical PQ phenomena, the cost of different mitigation solutions and the payback due to the adoption of particular solution. Furthermore, it accounts for different customers’ requirements and provides differentiated levels of PQ across the network. The simulation results present both the financial and technical benefits of the optimal mitigation scheme

Techno-economic analysis of global power quality mitigation strategy for provision of differentiated quality of supply

This paper presents a comprehensive methodology for techno-economic assessment of power quality (PQ) mitigation solutions, both network-based and device-based, and proposes an optimisation-based PQ mitigation strategy for delivering differentiated PQ in networks integrated with renewable generation. The proposed strategy is based on the evaluation of financial losses due to several critical PQ phenomena, the cost of different mitigation solutions and the payback due to the adoption of particular solution. Furthermore, it accounts for different customers’ requirements and provides differentiated levels of PQ across the network. The simulation results present both the financial and technical benefits of the optimal mitigation scheme

Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunity

Nordic Electricity Congestion's Arrangement as a Model for Europe: Physical Constraints or Operators' Opportunit