On-Load Network De-Icer Specification for a Large Transmission Network

Abstract

This paper presents a feasibility study conducted with a view to installing an on-load network de-icer (ONDI) for de-icing HV transmission lines forming part of the Matapédia subtransmission network operated by Hydro-Québec. The ONDI concept makes use of a phase-shifting transformer (PST) to induce very large ac currents to heat line conductors by the Joule effect. A single ONDI can handle a number of lines of different length with no need to transfer loads to other lines or disconnect them. In the study presented, more than 900 km of 230-and 315-kV HV circuits can be de-iced with one ONDI installed at Rimouski substation. To put the ONDI to work, only existing circuit breakers need to be operated so that no open-air (ice-sensitive) disconnecting switches are involved. The adequacy of this planning study is also discussed here with regard to taking into account uncertainties related to the weather conditions expected for severe ice storms.

Asynchronism of ice shedding from the de‐iced conductor based on heat transfer

“…The implementation of the method is confined to the power load demand of customers, and the optimisation degree of strategies and the accuracy of the ice-melting model greatly affect the actual results. Another on-load approach involves increasing the load current by using phase-shifting transformers while maintaining the voltage in the network [7]. This approach requires demanding performance of the transformer and has capacity limits, thus making it inapplicable in the de-icing of bundled conductors.…”

Multi‐objective transmission line de‐icing outage optimal scheduling framework

“…Much work has investigated various de‐icing techniques, among which the Joule effect is regarded as the most effective one, which melts ice on power lines by large AC or DC currents. AC de‐icing method can be divided into two categories: short‐circuit de‐icing [8] and on‐load de‐icing [9, 10]. The former requires large amount of reactive power and thus it is unfeasible to practice because of the limited reactive power.…”