Shaft turning parking bus for multiple unit installations utilizing a single motorized generator control system

In an electrical power generating installation of the type including a plurality of turbine-generator sets;

• a controlled variable frequency starting system;
• means for connecting the output from said starting system to the generator member of a selected turbine-generator pair for gradually increasing the frequency output of said starting system whereby to drive said generator as a synchronous motor to bring said turbine to a self-sustaining rotational velocity;
• means for disconnecting said generator from said system upon said turbine becoming self-sustaining;
• a power feeder network;
• and synchronization matching means for connecting said generator to said power feeder network upon a phase and frequency match being attained between said generator and power feeder network;
• the improvement enabling a single said starting system to be utilized in effecting transfer to a selected turbine-generator set to a low-speed turning configuration comprising:
• parking bus means;
• means for providing a potential to said parking bus means at a relatively constant, low frequency;
• switching means for disconnecting a selected turbine-generator set from said power feeder network and for re-connecting said turbine-generator set to said starting system;
• means for gradually reducing the frequency of said starting system output to gradually slow rotation of said turbine-generator set;
• means for matching the phase and frequency of rotation of said selected turbine-generator set to the corresponding phase and frequency of said parking bus;
• and
• means for switching and connecting the generator member of said selected turbine-generator set to said parking bus, to continue low speed turning of said selected turbine-generator set and for switching and reconnecting the generator member of said selected turbine-generator set to said starting system to bring said turbine-generator set into operating condition for reuse.

In an electrical power generating installation including a plurality of turbine-generator sets;

• a system for starting up selected turbine-generator sets and for enabling low speed, relatively constant angular velocity rotation of said sets for cool-down or other purposes;
• said system comprising:
• a variable frequency motorized generator starting system;
• means for connecting the output from said starting system to the generator member of a turbine-generator set selected for startup, to enable driving of said generator as a synchronous motor while gradually increasing the frequency of said power supply output to thereby bring said turbine to a self-sustaining rotational velocity;
• means for disconnecting said generator from said starting system upon said turbine becoming self-sustaining;
• a power feeder network;
• synchronization matching means connected to said power feeder network and to the output from said generator for effecting connection of said generator to said network upon a phase and frequency match being attained between the two;
• parking bus means;
• means for providing a potential to said parking bus at a substantially constant, relatively low frequency;
• means for disconnecting a selected turbine-generator set from said power feeder network and re-connecting said set to said starting system for gradually slowing rotation of said turbine-generator set by reducing the frequency of said starting system output;
• means for matching the phase and frequency of rotation of said selected turbine-generator set being driven by said starting system, to the corresponding phase and frequency of said parking bus;
• and
• means for thereupon connecting the generator member of said turbine-generator set to said parking bus, to effect continuing low-speed turning of said selected turbine-generator set.

In an electrical power generating installation of the type including a plurality of turbine-generator sets, and a controlled variable frequency starting system for starting up said turbine-generator sets by driving the generator members thereof as synchronous motors until speeds are reached at which said turbines are self-sustaining;

• a method enabling a single said starting system to be utilized in effecting transfer of a selected turbine-generator set at a low speed turning configuration for cooling or the like, comprising:
• a. providing a parking bus carrying a relatively constant and low-frequency potential thereon;
• b. disconnecting said selected turbine-generator set from the power feeder network and re-connecting said set to said starting system;
• c. gradually reducing the frequency of said starting system output to gradually slow rotation of said selected set;
• d. matching the phase and rotational frequency of said selected set to the corresponding phase and frequency of said parking bus;
• e. transferring the generator member of said set to said parking bus upon said match being attained;
• and
• f. thereafter continuing low speed turning of said set by driving said generator through said parking bus.

In an electrical power generating installation of the type including a plurality of turbine-generator sets, and a controlled variable frequency starting system for starting up said turbine-generator sets by driving the generator members thereof as synchronous motors until speeds are reached at which said turbine is self-sustaining;

• a method enabling a single said starting system to be utilized for both said start-up functions, and for enabling slow turning of a plurality of said sets for a sustained period for cooling or other purposes, said method comprising:
• a. providing a parking bus carrying a relatively constant and low frequency potential thereon;
• b. utilizing said starting system to bring a selected turbine-generator set to the approximate rotational speed corresponding to the frequency maintained on said parking bus;
• c. matching the phase and rotational frequency of said selected set to the corresponding phase and frequency of said parking bus;
• and
• d. electrically transferring the generator member of said set to said parking bus upon said match being attained, and thereafter continuing low speed turning of said set by driving said generator as a synchronous motor through said parking bus potential.