HIGH-POTENTIAL (HIPOT) TEST REQUIREMENTS FOR EXCITATION SYSTEMS FOR SYNCHRONOUS MACHINES VOLTAGE STANDARDS



Exciter power circuit
The exciter power circuit includes all components not electrically isolated from the exciter output. For static exciters, this includes the rectifier and thyristor circuits, transformer windings, line filters, shaft current suppressors, and any auxiliary components connected to either the input or output of the rectifier/thyristor bridge.

For rotating exciters, it includes armature windings, commutators, and brushes. For rotating exciter rated outputs 350 V dc or less, the ac rms test voltage shall be 10 times the rated output voltage of the exciter, but with a minimum of 1500 V.

For static exciter rated outputs 350 V dc or less, the ac rms test voltage shall be the greater of 10 times the rated output voltage of the exciter, but with a minimum of 1500 V, or twice the rated ac rms input voltage of the exciter plus 1000 V.

For rotating exciter rated outputs greater than 350 V dc, the ac rms test voltage shall be 2800 V plus twice the rated output voltage of the exciter. For static exciter rated outputs greater than 350 V dc, the ac rms test voltage shall be the greater of 2800 V plus twice the rated output voltage of the exciter, or twice the rated ac rms input voltage of the exciter plus 1000 V.

The synchronous-machine field winding is not included as it is covered by ANSI C50.10-1990. The exciter rated output voltage (for determination of the test voltage) shall not be less than the voltage
required at the associated generator field terminals when the generator is operated at rated kilovolt amperes, rated power factor, and rated voltage with the generator field winding at

- 75°C for field windings designed to operate at rating with a temperature rise of 60°C or less, or

- 100°C for field windings designed to operate at rating with a temperature rise greater than 60° C.

The exciter rated input voltage shall not be less than the voltage at the exciter input terminals when the generator is operated at rated kilovolt-amperes, rated power factor, and rated voltage with the generator field winding at

- 75°C for field windings designed to operate at rating with a temperature rise of 60°C or less, or

- 100° C for field windings designed to operate at rating with a temperature rise greater than 60° C.

All other circuits (electrically isolated from the exciter power circuit)
For circuits rated above 60 V or above 60 VA and not greater than 600 V, the ac rms test voltage shall be 1000 V plus twice the rated voltage. For circuits rated above 600 V, the ac rms test voltage shall be 2000 V plus 2.25 times the rated voltage.

Circuits rated at 60 V or less and 60 VA or less need not be given a high-potential test.

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