Paralleling control for phase synchronized generators

Claim 2

In an electrical power generation and distribution system having a first electrical power source including a generator having an alternating current output, the generator being powered by a variable speed engine through a constant speed drive, a second electrical power source having an alternating current output and switch means for connecting the outputs of the two sources in parallel, a paralleling control comprising: means providing an alternating current phase reference signal, the phase of which corresponds with that of said second alternating current source; means for comparing the phase of the output of said first source generator with the phase of said reference signal; means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with said constant speed drive to phase synchronize the first source generator with the reference signal; and means responsive to the phase comparator for actuating said switch means to connect the electrical source outputs in parallel, when the phase difference between the first source generator and the reference signal is within selected limits.

Claim 3

In an electrical power generation and distribution system having a first electrical power source including a generator having an alternating current output, the generator being powered by a variable speed engine through a constant speed drive, a second electrical power source having an alternating current output and switch means for connecting the outputs of the two sources in parallel, a paralleling control comprising: means providing an alternating current phase reference signal, the phase of which corresponds with that of said second alternating current source; means for comparing the phase of the output of said first source generator with the phase of said reference signal; means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with said constant speed drive to phase synchronize the first source generator with the reference signal; and means responsive to the phase comparator for actuating said switch means to connect the electrical source outputs in parallel, when the phase difference between the first source generator and the reference signal is within selected limits.

Claim 4

In an electrical power generation and distribution system having a first electrical power source including a generator having an alternating current output, the generator being powered by a variable speed engine through a constant speed drive, a second electrical power source having an alternating current output and switch means for connecting the outputs of the two sources in parallel, a paralleling control comprising: means providing an alternating current phase reference signal, the phase of which corresponds with that of said second alternating current source; means for comparing the phase of the output of said first source generator with the phase of said reference signal; means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with said constant speed drive to phase synchronize the first source generator with the reference signal; and means responsive to the phase comparator for actuating said switch means to connect the electrical source outputs in parallel, when the phase difference between the first source generator and the reference signal is within selected limits.

Claim 5

The paralleling control of claim 1 in which the means responsive to the phase difference signal for actuating said switch means is responsive to the cumulative phase difference signal.

Claim 6

The paralleling control of claim 1 in which the means responsive to the phase difference signal for actuating said switch means is responsive to the instantaneous phase difference between the generator and the reference.

Claim 7

The paralleling control of claim 1 in which said second source is an external power source and the refErence signal is derived from the external power source.

Claim 8

The paralleling control of claim 1 in which said second source is a second generator having an alternating current output, powered by a second variable speed engine through a second constant speed drive and including means for comparing the phase of the output of the second source generator with the phase of a reference signal and means responsive to the second phase comparator for developing a cumulative phase difference signal representing the cumulative difference in phase between the output of the second source generator and the reference, which is connected with the second constant speed drive to synchronize the second source generator with the reference signal.

Claim 9

The paralleling control of claim 5 in which each of said first and second electrical power sources has means providing an alternating current reference signal and including means for selecting one of the reference signals for the phase comparator of both power sources.

Claim 10

An electrical power generation and distribution system, comprising: a first electrical power source including a generator having alternating current output, the generator being powered by a first variable speed engine through a first constant speed drive; a second electrical power source including a second generator having an alternating current output, the generator being powered by a second variable speed engine through a second constant speed drive; a third electrical power source including an external alternating current supply; a first phase control for the first power source, including means for comparing the phase of the output of the first generator with that of a reference signal, and means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with the first constant speed drive to phase synchronize the first source with the reference signal; a second phase control for the second power source, including means for comparing the phase of the output of the second generator with that of a reference signal, and means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with the second constant speed drive to phase synchronize the second source with the reference signal; at least one source of alternating current phase reference signal associated with the first and second power sources; a source of alternating current phase reference signal associated with the third power source; a system for distributing electrical power from one or more of said sources to a load and including switch means operable independently for connecting each of the source outputs with the distribution system; and a paralleling control means for controlling the connection of a plurality of the power sources with the distribution system, including means for selecting one of the phase reference signals for the phase comparator of the first or second source connected or to be connected with the distribution system; and means responsive to the phase comparator for actuating said switch means to connect the electrical source outputs in parallel to the distribution system.

Claim 11

An electrical power generation and distribution system, comprising: a first electrical power source including a generator having alternating current output, the generator being powered by a first variable speed engine through a first constant speed drive; a second electrical power source including a second generator having an alternating current output, the generator being powered by a second variable speed engine through a second constant speed drive; a third electrical power source including an external alternating current supply; a first phase control for the first power source, including means for comparing the phase of the output of the first generator with that of a reference signal, and means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with the first constant speed drive to phase synchronize the first source with the reference signal; a second phase control for the second power source, including means for comparing the phase of the output of the second generator with that of a reference signal, and means responsive to the phase comparator for developing a cumulative phase difference signal which is connected with the second constant speed drive to phase synchronize the second source with the reference signal; at least one source of alternating current phase reference signal associated with the first and second power sources; a source of alternating current phase reference signal associated with the third power source; a system for distributing electrical power from one or more of said sources to a load and including switch means operable independently for connecting each of the source outputs with the distribution system; and a paralleling control means for controlling the connection of a plurality of the power sources with the distribution system, including means for selecting one of the phase reference signals for the phase comparator of the first or second source connected or to be connected with the distribution system; and means responsive to the phase comparator for actuating said switch means to connect the electrical source outputs in parallel to the distribution system.

Claim 12

The electrical distribution system of claim 7 in which the phase reference signal is selected in accordance with the electrical power sources which are connected to and which are to be connected to said distribution system.

Claim 13

The electrical distribution system of claim 8 in which the external power source is connected to or is to be connected to the distribution system and in which a signal representing the phase of the external power source is selected as the reference signal.

Claim 14

The electrical distribution system of claim 8 including means for selecting a single reference signal for said phase comparator to control the phase of each generator following the paralleling operation.

Claim 15

The electrical distribution system of claim 10 in which said selection meanS selects the phase reference signal from the external source when the external source is connected with the system.