Reference Letter of Main Power Systems of West Siberia

On 30 October 2019, the Main Power Systems of West Siberia informed that the Izolyator HV RIP bushings up to 500 kV that the company operates have proved to be reliable in various climate conditions.

Main power system of Western Siberia (MPS Western Siberia) operate on the territory of the Ural Federal District. The service area of the company includes 3 federal subjects of Russian Federation with a population over 3.5 mln residents. The networks provide electric connection between the unified energy systems of Siberia and Ural. MPS West Siberia is headquartered in Surgut, Tyumen region. MPS West Siberia is a subsidiary of the Federal Grid Company of the Unified Energy System.

In reply to your letter Ref No. 07/616 dated 28 October 2019, please be informed that the branch of FGC UES — MPS West Siberia purchased high-voltage bushings with RIP inslation with voltages up to 500 kV from Izolyator.

Over the period of operation at the facilities of MPS West Siberia, the equipment proved reliable and capable of operation in various climate conditions. We have no complaints to the product quality.

First Deputy General Director — Chief Engineer
V. V. Konishevsky’