Automatic generator synchronizing and connecting system and synchronizer apparatus for use therein

Claim 2

In a generator synchronizing system, in combination, circuit means adapted to be operatively connected to an energized alternating current bus and to an alternating current generator of different frequency for obtaining square waves corresponding to the bus and generator waveforms, the circuit means including means for utilizing the square waves corresponding to the bus and generator waveforms to obtain a triangular phase difference signal and a level detector having the triangular phase difference signal applied thereto, said level detector including threshold value establishing means, said threshold value being attained by said triangular phase difference signal a constant time before phase coincidence irrespective of the frequency difference between the bus and generator voltages, and normally open circuit breaker means interconnecting the bus and generator, said circuit breaker means having an inherent closing time substantially equal to said constant time, the first-named circuit means being operatively connected to the circuit breaker means and applying a closing signal to the circuit breaker means when said threshold value is attained by said triangular phase difference signal.

Claim 3

In combination, circuit means adapted to be connected to an alternating current bus and to an oncoming alternating current generator the frequency of which is changing and approaching the frequency of the bus for obtaining two signals the first of said signals occurring at a definite phase before phase coincidence of the bus and generator, the second of said signals occurring at a definite time before phase coincidence, other circuit means for ascertaining which of said signals occurs before the other, a normally open circuit breaker interconnecting the bus and generator, said circuit breaker having a closing coil and a predetermined inherent closing time substantially equal to said definite time before phase coincidence, and means including a source of potential interconnecting the closing soil and the means for ascertaining which of said signals occurs before the other for applying current to the closing coil when the first signal occurs before the second signal.

Claim 4

In combination, circuit means adapted to be connected to an alternating current bus and to an oncoming alternating current generator the frequency of which is changing and approaching the frequency of the bus for obtaining two signals the first of said signals occurring at a definite phase before phase coincidence of the bus and generator, the second of said signals occurring at a definite time before phase coincidence, other circuit means for ascertaining which of said signals occurs before the other, a normally open circuit breaker interconnecting the bus and generator, said circuit breaker having a closing coil and a predetermined inherent closing time substantially equal to said definite time before phase coincidence, and means including a source of potential interconnecting the closing soil and the means for ascertaining which of said signals occurs before the other for applying current to the closing coil when the first signal occurs before the second signal.

Claim 5

A synchronizing system for use in conNecting an oncoming alternating current generator in parallel with an energized alternating current bus wherein a normally open circuit breaker interconnect the bus and generator, said circuit breaker having an inherent closing time after a closing signal is applied thereto, and the generator has means operatively connected thereto for increasing the speed in response to an ''''increase speed'''' signal and decreasing the speed in response to a ''''decrease speed'''' signal, and the generator has means operatively connected thereto for increasing the voltage in response to an ''''increase voltage'''' signal and means for decreasing the voltage in response to a ''''decrease voltage'''' signal, in combination, synchronizer circuit means adapted to supply a closing signal to the circuit breaker, converter means operatively connected to the bus and generator for producing a phase difference waveform, speed matcher circuit means operatively connected to the converter means and having the phase difference waveform applied thereto, said speed matcher circuit means being operatively connected to the bus and generator and having applied thereto first and second signals corresponding to the bus frequency and the generator frequency respectively, said speed matcher circuit means utilizing the first and second signals and the phase difference waveform to generate for application to the generator ''''increase speed'''' and ''''decrease speed'''' signals selectively in accordance with the relative frequencies of said first and second signals, voltage matcher circuit means operatively connected to the bus and generator and selectively generating for application to the generator ''''increase voltage'''' and ''''decrease voltage'''' signals in accordance with the relative voltages of the bus and generator, voltage acceptor circuit means operatively connected to the bus and generator and to the synchronizer, said voltage acceptor circuit means disabling the synchronizer circuit means until the bus and generator voltages are within an acceptable range of each other and deviate from a selected center voltage by an acceptable amount, the synchronizer circuit means thereafter being readied to supply a closing signal to the circuit breaker, said synchronizer circuit means utilizing the bus and generator frequencies and the phase difference waveform to generate a closing signal for the circuit breaker at a time before phase coincidence of the bus and generator voltages equal to the inherent closing time of the circuit breaker.

Claim 6

A synchronizing system for use in conNecting an oncoming alternating current generator in parallel with an energized alternating current bus wherein a normally open circuit breaker interconnect the bus and generator, said circuit breaker having an inherent closing time after a closing signal is applied thereto, and the generator has means operatively connected thereto for increasing the speed in response to an ''''increase speed'''' signal and decreasing the speed in response to a ''''decrease speed'''' signal, and the generator has means operatively connected thereto for increasing the voltage in response to an ''''increase voltage'''' signal and means for decreasing the voltage in response to a ''''decrease voltage'''' signal, in combination, synchronizer circuit means adapted to supply a closing signal to the circuit breaker, converter means operatively connected to the bus and generator for producing a phase difference waveform, speed matcher circuit means operatively connected to the converter means and having the phase difference waveform applied thereto, said speed matcher circuit means being operatively connected to the bus and generator and having applied thereto first and second signals corresponding to the bus frequency and the generator frequency respectively, said speed matcher circuit means utilizing the first and second signals and the phase difference waveform to generate for application to the generator ''''increase speed'''' and ''''decrease speed'''' signals selectively in accordance with the relative frequencies of said first and second signals, voltage matcher circuit means operatively connected to the bus and generator and selectively generating for application to the generator ''''increase voltage'''' and ''''decrease voltage'''' signals in accordance with the relative voltages of the bus and generator, voltage acceptor circuit means operatively connected to the bus and generator and to the synchronizer, said voltage acceptor circuit means disabling the synchronizer circuit means until the bus and generator voltages are within an acceptable range of each other and deviate from a selected center voltage by an acceptable amount, the synchronizer circuit means thereafter being readied to supply a closing signal to the circuit breaker, said synchronizer circuit means utilizing the bus and generator frequencies and the phase difference waveform to generate a closing signal for the circuit breaker at a time before phase coincidence of the bus and generator voltages equal to the inherent closing time of the circuit breaker.

Claim 7

Apparatus according to claim 3 in which the converter means is additionally characterized as producing square waves from substantially sinusoidal bus and generator waveforms, and said speed matcher circuit means utilizes the square waves together with the phase difference waveform to selectively produce said ''''increase speed'''' and ''''decrease speed'''' signals for application to the generator.

Claim 8

Apparatus according to claim 3 including in addition lockout means in the synchronizer for preventing synchronization if the angle in advance of synchronism at which the circuit breaker closing circuit must be energized exceeds a specific value.

Claim 9

Apparatus according to claim 3 in which the circuit breaker is additionally characterized as having auxiliary contacts, and circuit means connecting the auxiliary contacts to the synchronizer, the synchronizer including a circuit for preventing pumping of the circuit breaker.

Claim 10

In automatic generator synchronizer apparatus, circuit means adapted to be operatively connected to an energized bus and an oncoming generator for converting the bus and generator voltages to square waves and utilizing said square waves to produce a signal at a definite phase advance angle between bus and generator voltages, and other circuit means for producing an additional signal at a definite time before synchronism in accordance with the inherent closing time of a circuit breaker interposed between the bus and the oncoming geneRator.

Claim 11

In automatic generator synchronizer apparatus, circuit means adapted to be operatively connected to an energized bus and an oncoming generator for converting the bus and generator voltages to square waves and utilizing said square waves to produce a signal at a definite phase advance angle between bus and generator voltages, and other circuit means for producing an additional signal at a definite time before synchronism in accordance with the inherent closing time of a circuit breaker interposed between the bus and the oncoming geneRator.

Claim 12

Apparatus according to claim 7 including a circuit breaker, and means for supplying a closing signal to the circuit breaker when the phase advance signal proceeds the synchronizing signal.

Claim 13

Apparatus according to claim 8 including in addition logic circuitry for ascertaining whether the last named signal occurs before the synchronizing signal.

Claim 14

Apparatus according to claim 7 in which the circuit means for producing said additional signal includes means for converting the bus and generator voltages to square waves of constant amplitudes, means for mixing the square waves of constant amplitudes to obtain a true, triangular phase difference waveform, means for applying the phase difference waveform to a differentiator and to a summing circuit, circuit means for applying the output of the summing circuit to the discriminator, said discriminator producing said additional signal at a definite time before phase coincidence of the bus and generator voltages independent of a frequency difference between them.

Claim 15

Apparatus according to claim 6 where the circuit for preventing pumping includes a normally open contact on the circuit breaker, timer means and bistable circuit means, said bistable circuit means being set by the circuit breaker thus preventing synchronization, said timer means starting a timing period when the bistable is set and after a predetermined time resetting the bistable circuit means if the circuit breaker remains closed for said predetermined time, the bistable circuit means thus permitting synchronization.