Repairs and modifications. Existing electrical substations may be repaired or maintained without restriction. However, any and all modifications, additions, deletions or changes to an electrical substation that operate under a special use permit, whether structural or not, shall be made by special use permit, except that such special use permit shall not be required for repairs which become necessary in the normal course of use of such electrical substations or become necessary as a result of natural forces, such as wind or ice. While facilities may be repaired and maintained without restriction, any modification to any such facility, whether or not incidental to repair or maintenance, which may result in a change in the surface, subsurface, or air space occupied by such facility, including any device used in connection with the same, shall be subject to the provisions of this chapter and special use permit regulation(s).