Interference effects between HVDC circuits and nearby metallic infrastructure

	Mohammad Nazemi Convenor JWG C4/B1/B2/B4.78		Marta Val Escudero Chair SC C4

 

Background

 

To achieve the goal of climate neutrality, the transport routes for renewable energy must continue to be expanded. The energy transmission will primarily be realized in the form of HVDC systems, allowing for nearly loss-free transmission over long distances. Due to the densely built infrastructures within the transport routes, interference between HVDC transmission systems and parallel metallic infrastructures like buried pipelines is unavoidable.

 

Although DC technology, particularly when using underground cables (HVDC cables), does not cause electromagnetic interference during normal operation, it can still influence parallel metallic infrastructures under transient conditions.

 

The interference between AC transmission systems and parallel buried infrastructure (AC-Interference) is well understood and addressed in different standards and guidelines as well as in Cigre TB95. However, current standard approaches for calculating and assessing the AC-interferences (under fault condition) are not applicable for calculation and evaluation of the interference between HVDC systems (HVDC cables as well as HVDC overhead lines) and parallel buried infrastructure (DC-Interference).     

A methodology for the calculation and evaluation of DC-Interference needs to be developed. The calculation must be conducted in the time domain simulation to properly consider the complexity of the couplings. With the new approach, the minimum distance between HVDC systems and the buried infrastructure as well as the maximum length of the parallelism can be determined. 

 

Aim & Purpose of the Working Group

 

The primary goal of the joint working group JWG C4/B1/B2/B4.78 is to study the interference effects between HVDC transmission circuits and neighbouring metallic pipelines and, if necessary, propose measures to prevent negative consequences on these surrounding infrastructures as well as on the considered DC transmission circuit. The focus of the work should be mainly on safety issues. The working group shall also review the international relevant regulatory context and identify potential gaps.

 

Scope

 

The scope of work includes the following topics:

• Review of existing literature related to DC-interference with nearby metallic structures (e.g. pipelines, fences and telecommunication lines) and highlight the differences or similitudes between AC and DC-interferences.
• Problem statement: focus on the interference effects between HVDC circuits and nearby metallic infrastructure; cause and effects.
• Clarification of the regulatory context related to DC-interference.
• Development of calculation methodologies (and measurements methods) for DC-Interference.
• If necessary, presentation of mitigation and protection measures for DC-Interference.