Medium or high voltage power generation is often used where the power ratio causes the low voltage current to exceed practical limits. In practical terms, this happens when the system capacity is 4000 amps or more. It may also be desirable to distribute power to points at significant distances from the generator set. A good application of equipment commonly considered for Medium Voltage application is single generator rated above 2.5 MVA and parallel generators rated above 2 MVA.

Medium voltage alternators are not economically practical at a ratio less than 1000 kW approximately. It is desirable to consider the use of a low voltage machine of levels less than 1000 kW and possibly with a step-down transformer. When designing a medium voltage or high voltage installation, attention must be paid to the training and competence of the personnel operating the system due to the higher level of safety precautions required for these systems.

In generator systems where medium voltage alternator is used;

• Transmission losses and voltage drop are reduced,  
• Efficiency of the distribution system increases,
• Installation and maintenance costs are reduced,
• Since there is no need for bulky cables, both the appearance is intact and the security is increased.