Is it technically possible to operate 66kv HV switchyard eqipments for substation in 33kv system?

Technically, operating 66 kV high voltage switchyard equipment in a 33 kV system is generally not advisable due to differences in voltage ratings, insulation requirements, and operational standards. While the equipment may physically function at a lower voltage, it may not meet safety and regulatory requirements, and could pose risks of insulation failure or equipment damage. Additionally, protective relaying and control systems designed for 66 kV may not operate correctly at 33 kV. Therefore, it's crucial to use equipment rated for the specific operating voltage of the system.