- AG C4.1: Strategic Directions
- AG C4.2: Institutional Liaison
- AG C4.3: Tutorials and Conferences
- JWG A1/C4.52 Wind generators and frequency-active power control of power systems
- JWG A2/C4.309 Electrical Transient Interaction between Transformers and the Power System
- JWG A2/C4.52 High-frequency transformer and reactor models for network studies
- JWG A3/B5/C4.37 System conditions for and probability of Out-of-Phase
- JWG B4/B1/C4.73 Surge and extended overvoltage testing of HVDC Cable Systems
- JWG B5/C4.61 Impact of Low Inertia Network on Protection and Control
- JWG C1/C4.36 Review of Large City & Metropolitan Area power system development trends taking into account new generation, grid and information technologies
- JWG C2/C4.37 Recommendations for Systematic Framework Design of Power System Stability Control
- JWG C4.24/CIRED Power Quality and EMC Issues Associated with Future Electricity Networks
- JWG C4.31/CIRED EMC between Communication Circuits and Power Systems
- JWG C4.40/CIRED Revisions to IEC Technical Reports 61000-3-6, 61000-3-7, 61000-3-13, and 61000-3-14
- JWG C4.42/CIRED Continuous assessment of low-order harmonic emissions from customer installations
- JWG C4/B4.38 Network Modelling for Harmonic Studies
- JWG C4/B4/C1.604 Influence of Embedded HVDC Transmission on System Security and AC Network Performance
- JWG C4/B5.41 Challenges with series compensation application in power systems when overcompensating lines
- JWG C4/C6.29 Power Quality Aspects of Solar Power
- JWG C4/C6.35/CIRED Modelling and dynamic performance of inverter based generation in power system transmission and distribution studies
- WG C4.111 Review of LV and MV Compatibility Levels for Voltage Fluctuation
- WG C4.112 Power Quality Monitoring in Flexible Power Networks
- WG C4.206 Protection of the High Voltage Power Network Control Electronics Against Intentional Electromagnetic Interference (IEMI)
- WG C4.207 EMC with communication circuits, low voltage systems and metallic structures
- WG C4.208 EMC in HV Substations and Generating Stations
- WG C4.23 Guide to Procedures for Estimating the Lightning Performance of Transmission Lines
- WG C4.25 Issues related to ELF Electromagnetic Field exposure and transient contact currents
- WG C4.26 Evaluation of Lightning Shielding Analysis Methods for EHV and UHV DC and AC Transmission-lines
- WG C4.27 Benchmarking of Power Quality Performance in Transmission Systems
- WG C4.28 Extrapolation of measured values of power frequency magnetic fields in the vicinity of power links
- WG C4.30 EMC in Wind Generation Systems
- WG C4.303 Pollution and Environmental Influence on Electrical Performance
- WG C4.305 Practices in Insulation Coordination of Modern Electric Power Systems Aimed at the Reduction of the Insulation Level
- WG C4.306 Insulation Coordination of UHV AC systems
- WG C4.307 Resonance and Ferroresonance in Power Networks and Transformer Energization Studies
- WG C4.32 Understanding of the Geomagnetic Storm Environment for High Voltage Power Grids
- WG C4.33 Impact of Soil-Parameter Frequency Dependence on the Response of Grounding Electrodes and on the Lightning Performance of Electrical Systems
- WG C4.34 Application of Phasor Measurement Units for monitoring power system
- WG C4.36 Winter Lightning – Parameters and Engineering Consequences for Wind Turbines
- WG C4.37 Electromagnetic Computation Methods for Lightning Surge Studies with Emphasis on the FDTD Method
- WG C4.39 Effectiveness of line surge arresters for lightning protection of overhead transmission lines
- WG C4.407 Lightning Parameters for Engineering Applications
- WG C4.408 Lightning Protection of Low-Voltage Networks
- WG C4.409 Lightning Protection of Wind Turbine Blades
- WG C4.410 Lightning Striking Characteristics to Very High Structures
- WG C4.43 Lightning problems and lightning risk management for nuclear power plants
- WG C4.44 EMC for Large Photovoltaic Systems
- WG C4.45 Measuring techniques and characteristics of fast and very fast transient overvoltages in substations and converter stations
- WG C4.46 Evaluation of Temporary Overvoltages in Power Systems due to Low Order Harmonic Resonances
- WG C4.47 Power System Resilience (PSR WG)
- WG C4.48 Overvoltage Withstand Characteristics of Power System Equipment 35-1200 kV
- WG C4.49 Multi-frequency stability of converter-based modern power systems
- WG C4.50 Evaluation of Transient Performance of Grounding Systems in Substations and Its Impact on Primary and Secondary Systems
- WG C4.501 Numerical Electromagnetic Analysis and Its Application to Surge Phenomena
- WG C4.502 Power system technical performance issues related to the application of long HVAC cables
- WG C4.503 Numerical techniques for the computation of power systems, from steady-state to switching transients
- WG C4.603 Analytical Techniques and Tools for Power Balancing Assessments
- WG C4.605 Modelling and aggregation of loads in flexible power networks
JWG C4.42/CIRED Continuous assessment of low-order harmonic emissions from customer installations
Background:
Harmonic voltage distortion remains an important issue in power networks and utilities are fully aware of the impact this creates on power quality. With the increasing number of power electronic loads, harmonic interactions and inverter based generation, e.g. PV and wind, the issue is likely to become more exacerbated in the future. A proper determination and quantification policy for low-order harmonic emission levels could help restrain harmonic voltage distortion in power networks. For example, an incentive based policy could compel the customers to keep the harmonic emission levels inside required limits, but the assessment of the harmonic emissions remains a challenge. Basic guidelines on the assessment of the harmonic emission levels are provided within the IEC TR 61000-3-6. However, the detailed methods to determine the harmonic emission levels remain complex and highly difficult to be used in practice. The assessment should preferably run continuously with the statistical evaluation of results and not as a single-shot (at certain time instant) or two-step (before and after the connection of installation) procedure. In recent years many techniques were proposed to determine the harmonic emission levels but for various reasons none of them is widely used in practice, i.e. these methods require the knowledge of the actual network data in terms of system impedance. The aim of the work is to review the current industry practice and the new technologies and approaches available in this field and to propose practical guidelines for online monitoring and continuous assessment of low-order harmonic emissions from disturbing customer installations.
Scope:
1. Review of harmonic emission assessment methods with present background distortion based on the IEC approach (basic definition of emission)
2. Evaluation of methods for system harmonic impedance determination (invasive and non-invasive methods, reference impedance) with non-invasive methods being based on natural fluctuation of loads (regression methods)
3. Consideration of technical limitations related to harmonics measurements (CTs and VTs) and sensitivity analysis (measurement errors, system impedance estimation error)
4. Consideration of statistical assessment of results, i.e. 95% value in 1 week, aggregation of results (intervals 200 ms, 3 s, 10 min, …)
5. Recommendation and specification of a clearly defined methodology with clear instructions for practical implementation
Time Schedule : Start : May 2015 Final report : December 2018
Convener:Igor Papič (Slovenia)