Protective apparatus, methods of operating same and phase window adjusting apparatus for use therein

Protective apparatus for use in an A.C. electrical power system with a circuit breaker for connecting and disconnecting electrically energizable conductors of a polyphase line from corresponding electrically energizable conductors of a polyphase bus, the circuit breaker having auxiliary contacts defining the state of the circuit breaker as open or closed, the protective apparatus comprising:

• means responsive to the auxiliary contacts for producing a first signal representative of the state of the breaker as open or closed;
• means connected to the means for producing the first signal and operable in response to the first signal for providing a second signal only when the breaker is closed and a discrepancy occurs in the magnitudes of the voltages of the line and bus between conductors of the line, between conductors of the bus or between the line and the bus;
• and
• means for providing an alarm output representative of malfunction when the second signal occurs.

A method of operating protective apparatus for use in an A.C. electrical power system with a circuit breaker for connecting and disconnecting electrically energizable conductors of a polyphase line from corresponding electrically energizable conductors of a polyphase bus, the circuit breaker having auxiliary contacts defining the state of the circuit breaker as open or closed, the method comprising the steps of:

• producing a first signal representative of the state of the breaker as open or closed;
• providing a second signal only when the breaker is closed and a discrepancy occurs in the magnitudes of the voltages of the line and bus between conductors of the line, between conductors of the bus or between the line and bus;
• and
• providing an alarm output representative of malfunction when the second signal occurs.

A method of operating protective apparatus for use in an A.C. electrical power system with a circuit breaker for connecting and disconnecting first and second electrical conductors that are electrically energizable, the conductors normally having a negligible phase difference of electrical energization when the circuit breaker is closed, the circuit breaker having auxiliary contacts defining the state of the circuit breaker as open or closed, the method comprising the steps of:

• producing a first signal representative of the state of the breaker as open or closed;
• generating a second signal only when the breaker is closed and the phase difference of electrical energization of the first and second electrical conductors exceeds a predetermined value;
• and
• providing an alarm output representative of malfunction when the second signal occurs.

Protective apparatus for use in an A.C. electrical power system with a circuit breaker for connecting and disconnecting first and second electrical conductors that are electrically energizable, the conductors normally having a negligible phase difference of electrical energization when the circuit breaker is closed, the circuit breaker having auxiliary contacts defining the state of the circuit breaker as open or closed, the protective apparatus comprising:

• means responsive to the auxiliary contacts for producing a first signal representative of the state of the breaker as open or closed;
• means connected to the means for producing the first signal and operable in response to the first signal for generating a second signal only when the breaker is closed and the phase difference of electrical energization of the first and second electrical conductors exceeds a predetermined value;
• and
• malfunction timer means operable in resonse to the second signal for providing an alarm output representative of malfunction when a condition persists in excess of a predetermined time period wherein the breaker is closed and the phase difference of electrical energization of the first and second electrical conductors exceeds the predetermined value.

Protective apparatus for use in an A.C. electrical power system with a circuit breaker for connecting and disconnecting electrically energizable conductors of a polyphase line from corresponding electrically energizable conductors of a polyphase bus, the circuit breaker having auxiliary contacts defining the state of the circuit breaker as open or closed, the protective apparatus comprising:

• means responsive to the auxiliary contacts for producing a first signal representative of the state of the breaker as open or closed;
• means connected to the means for producing the first signal and operable in response to the first signal for generating a second signal only when the breaker is closed and a discrepancy occurs in the magnitudes of the voltages of the line and bus between conductors of the line, between conductors of the bus or between the line and bus;
• and
• malfunction timer means operable in response to the second signal for providing an alarm output representative of malfunction when a condition persists in excess of a predetermined time period wherein the breaker is closed and the discrepancy in the magnitudes of voltages is present.