Differential fault current protection of a multiprocessor controlled electric power generating system

A fault current detection isolation and clearing system for use in an integrated power generating and distributing arrangement having multiple generators, including in combination:

• first and second generators, each having a set of neutral armature conductors and a set of output conductors;
• said set of output conductors of said first generator electrically connected through a first breaker to a load and to one side of a second breaker;
• said set of output conductors of said second generator electrically connected to another side of said second breaker through a distribution bus;
• a first current detection circuit means coupled respectively to said set of neutral armature conductors of said first generator, said set of output conductors between said first breaker and said load, and to said distribution bus, said first current detection circuit providing a differential current output signal only when a fault exists and is detected by said coupling to any one of said set of neutral armature conductors, said set of output conductors and said distribution bus;
• a second current detection circuit means coupled to said set of output conductors from said first generator at a point between said first breaker and said second breaker, said second current detection circuit means providing an output signal whenever a fault exists and is detected by said second current transformer circuit means;
• said first and second breakers each having a breaker control means;
• a power control logic network electrically coupled to said first current detection circuit means output and said second current detection circuit output, said power control logic network having an output electrically connected to said breaker control means to control breaker action in response to faults detected within the system as a function of circuit breaker conditions.

A current detection and clearing system for use in an integrated power generating and distribution arrangement having multiple generators including in combination:

• first, second and third generators having neutral armature windings and generator circuit breakers connecting said first and second generators to first and second loads, and said third generator to a tie bus;
• bus tie breakers connected in series and between respectively said first load and said tie bus and said second load and said tie bus;
• first, second, third and fourth differential fault current detection circuits, each of said first and second differential fault current detection circuits providing outputs indicative of a fault detected between the neutral armature windings respectively of said first and second generator, the first and second load and the bus tie, said third differential fault detection circuit providing an output indicative of a fault detected between the neutral armature windings of the third generator and the tie bus;
• said fourth differential fault detection circuit providing an output indicative of a fault detected between respectively the first load and said bus tie breaker and the second load and said bus tie breaker and between the third generator and said third generator circuit breaker;
• each of said breakers having a breaker condition detection means which provides an output indicative of the breaker condition;
• each of said breakers further including a breaker control means which allows independent control of each of said breakers;
• and
• a power control logic network electrically coupled to said circuit breaker condition detection means output and to the outputs of said first, second, third and fourth fault detection circuits, said power control logic network having an output electrically connected to each breaker control means to control breaker action in a programmed manner in response to faults detected within said integrated power generating and distribution arrangement.

A differential fault current detection system for use in a power generating and distribution arrangement having multiple generators, including in combination:

• a first generator, second generator and auxiliary generator, each having a set of neutral armature conductors and a set of output conductors;
• said set of output conductors of said first and said second generators respectively electrically connected through a first generator circuit breaker and a second generator circuit breaker to a first load and a second load and to one side of a first bus tie breaker and a second bus tie breaker;
• said set of output conductors of said auxiliary generator connected through an auxiliary bus tie breaker respectively to the other side of each of said first and second bus tie breakers through a tie bus;
• a first generator differential fault current transformer circuit means inductively coupled respectively to said set of neutral armature conductors of said first generator, said set of output conductors between said first generator circuit breaker and said first load, and to said tie bus;
• a second generator differential fault current transformer circuit means inductively coupled respectively to said set of neutral armature conductors of said second generator, said set of output conductors between said second bus tie breaker and said second load, and to said tie bus;
• said first and second generator differential fault current transformer circuits providing an output signal only when a fault exists and is detected by said inductive couplings to any one of said sets of neutral armature conductors, said sets of output conductors and said tie bus;
• a tie bus differential fault current detection circuit means inductively coupled to said sets of output conductors respectively from said first and said second generators at points between said first and second generator circuit breakers and said first and second bus tie breakers, said tie bus differential fault current detection circuit means is also coupled to said set of output conductors of said auxiliary generator;
• said tie bus differential fault current detection circuit means providing an output whenever a fault exists and is detected by said tie bus differential fault current detection circuit means;
• said first and second generator circuit breakers, said first and second tie breakers and said auxiliary bus tie breaker each having a breaker control means and a circuit breaker condition detection means, said circuit breaker condition detection means having an output lead connect thereto upon which appears a signal indicative of the circuit breaker condition;
• a power control logic network electrically coupled to said circuit breaker condition detection means output and to the outputs of said first and second generator differential fault current transformer circuit means, and said tie bus differential current detection circuit means;
• and
• said power control logic network having an output electrically connected to each breaker control means to control breaker action in a programmed manner in response to the condition of said breakers and faults detected within the system.