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EMPIR project publishes several papers on high-voltage electricity networks

Power pylons against a cloudy sky

The project has presented its papers at a number of conferences and produced both masters and PhD theses

The project

Many renewable energy sources, such as hydroelectric reservoirs and offshore wind plants, are located more than 1000 km away from the consumers they supply. High voltage DC (HVDC) networks are the only efficient and economical solution for transmission across these distances and so will be key for the uptake of these renewable sources.

‘Impulses’ – surges in voltage that peak very quickly but take a much longer time to dissipate – are an important phenomenon affecting these networks. To ensure resilience of the power supply, network components must be resistant to both ‘lightning impulses’ (e.g., from lightning strikes) and ‘switch impulses’ (e.g., from changes in operations). These impulses become superimposed over the electricity already flowing through the system, altering its waveform and causing damage to transmission lines and substations.

Testing components for these future transmission grids therefore requires the application of superimposed voltage forms. However, these ‘composite’ voltage tests have been carried out in the test laboratories without sufficient metrological traceability and standardisation.

EMPIR project Support for standardisation of high voltage testing with composite and combined wave shapes (19NRM07, HV-com2) has investigated the effects these impulses on high voltage AC and DC networks, assessing new and existing measurement systems and determining the effects of composite voltages on the degradation of high voltage grid components.

Papers published

The project has also published a number of papers including:

‘Universal Measuring Unit for High Voltage Measurements’, presented by TAU at 27th Nordic Insulation Symposium (NORD-IS)
‘Design and Verification of a Calculable Composite Voltage Calibrator’, presented by VTT at NORD-IS
‘The Usage of High Voltage Amplifiers to Setup Reference Calibrators for Combined and Impulse Voltages up to 1 kV’, presented by LNE at NORD-IS
‘Reference Calibrator for Combined and Composite High Voltage Impulse Tests’, presented by LNE at the 22nd International Symposium on High Voltage Engineering
‘Prequalification of Capacitors for High-Precision Voltage Dividers’, presented by TUG at the 22nd International Symposium on High Voltage Engineering
‘Development of standardized definitions for Combined and Composite High Voltage Tests’, published by INRIM

Project partner TAU has also produced two master’s theses – ‘Development and testing of software for evaluation of high voltage composite and combined waveforms’ and ‘Testing and analysis of universal high voltage divider’ – while PTB has produced one PhD thesis – ‘Metrological infrastructure for the measurement of superimposed impulse voltages in HVDC systems.’

Project coordinator Johann Meisner (PTB) has said about the work of the project:

“After the successful outcome of many tasks in the project, the project partners have jointly released six peer reviewed publications in the last few months. The publication of results on the definition and development of reference calibrators for combined and composite waveforms was the main focus. Furthermore, a method for qualifying components for universal dividers was published. All these results are made available in recommendation reports for TC 42.”

This EMPIR project is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR Participating States.

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