Urgent live repair of OHL Burshtynska TPP – Mukacheve was carried in the middle of October. It allowed to avoid the overload of the 220kV trunk power grids of Burshtynska TPP Island, possible reduction of reliability of Mukachevo power node for consumers, and limitations of electricity exports.
Urgent live repair was carried out by the line crew of the specialised unit of Ukrenergo, Vinnytsiaelektrotekhnolohiia, at the intermediate tower №426 of OHL 400kV Burshtynska TPP – Mukacheve, located on the Lysychovskyi mountain pass in Zakarpatska oblast.
A defect in the line was discovered the day before by line staff of Zakhidna PS during a scheduled inspection. Part of the OHL 400kV of Burshtynska TPP – Mukacheve came out of the supporting clamp of the phase wire and hung in the air.
Switching off the OHL 400kV of Burshtynska TPP – Mukacheve for repairing would lead to limitations of electricity exports to European consumers. Burshtynska TPP Island has two main lines, through which power is output, namely OHL 750kV Zakhidnoukrainska – Albertirsha and OHL 400kV Burshtynska TPP – Mukacheve. The first one at that time was under reconstruction. Thus, even for a short time, de-energizing the OHL 400kV Burshtynska TPP – Mukacheve would disrupt the flow balance at the interstate crossing, overload and possibly shutdown of 220kV Island equipment. There was a risk of an emergency situation and de-energization for consumers.
It was decided to conduct live works. Such work is performed by workers of Vinnytsiaelektrotekhnolohiia. However, the Zakarpattia case was more complicated than the previous cases.
First of all, it is the higher voltage. Previously, the trouble shooters operated at a voltage not higher than 330kV. Although during the training the technology of live works under 400kV and even 750kV has been worked out.
Besides, the type of tower as well as its location made it difficult to repair. The object is high in the mountains and the access roads are almost 45° inclined and allow accessing only in dry weather. So it was required to act quickly.
After the assessment of the situation in situ by the specialists of Vinnytsiaelektrotekhnolohiia, a technological map of works was developed and additional equipment manufactured. Repairing itself took about 5 hours.
Under new electricity market conditions, live works guarantee uninterrupted power supply for consumers, and allows avoiding possible limitations of generation and minimises the risks of transmission interraptions in interstate power grids.