Solid-state trip device comprising a zero sequence current detection circuit
First Claim
Patent Images
1. A multipole electrical circuit breaker, protecting an A.C. electrical supply system, including a solid-state trip device, comprising:
- a current sensor per pole, which generates a signal proportional to the current flowing through the associated conductor of the supply system protected by the circuit breaker;
a detection and rectification circuit to which said signals are applied to supply on the one hand signals representative of the currents flowing through the conductors to be protected and on the other hand a zero sequence signal if an insulation fault occurs; and
an electronic processing unit to which the output signals from the detection and rectification circuit are applied to perform delayed and/or instantaneous tripping functions and delivering, with or without a time delay, a circuit breaker tripping order when preset thresholds are exceeded by the signals representative of the currents flowing through the conductors or by the zero sequence signal, wherein the detection and rectification circuit comprises first rectification means producing a first signal representative of the sum of the positive half-waves of the output signals from the set of current sensors, second rectification means producing a second signal representative, in absolute value, of the sum of the negative half-waves of the output signals from the set of current sensors, and means effecting the difference between the first and second summed signals so as to produce said zero sequence signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A signal representative of the zero sequence current is obtained from current transformers associated with each phase and with the neutral if applicable by separate summing, in two distinct conductors, of the positive half-wave currents and of the absolute value of the negative half-wave currents produced by the set of current transformers, the difference between the currents flowing through these two conductors being representative of the zero sequence current.
-
Citations
7 Claims
-
1. A multipole electrical circuit breaker, protecting an A.C. electrical supply system, including a solid-state trip device, comprising:
-
a current sensor per pole, which generates a signal proportional to the current flowing through the associated conductor of the supply system protected by the circuit breaker; a detection and rectification circuit to which said signals are applied to supply on the one hand signals representative of the currents flowing through the conductors to be protected and on the other hand a zero sequence signal if an insulation fault occurs; and an electronic processing unit to which the output signals from the detection and rectification circuit are applied to perform delayed and/or instantaneous tripping functions and delivering, with or without a time delay, a circuit breaker tripping order when preset thresholds are exceeded by the signals representative of the currents flowing through the conductors or by the zero sequence signal, wherein the detection and rectification circuit comprises first rectification means producing a first signal representative of the sum of the positive half-waves of the output signals from the set of current sensors, second rectification means producing a second signal representative, in absolute value, of the sum of the negative half-waves of the output signals from the set of current sensors, and means effecting the difference between the first and second summed signals so as to produce said zero sequence signal.
-
-
2. A multipole electrical circuit breaker, protecting an A.C. electrical supply system, including a solid-state trip device, comprising:
-
a current sensor per pole, which generates a signal proportional to the current flowing through the associated conductor of the supply system protected by the circuit breaker; a detection and rectification circuit to which said signals are applied to supply on the one hand signals representative of the currents flowing through the conductors to be protected and on the other hand a zero sequence signal if an insulation fault occurs; and an electronic processing unit to which the output signals from the detection and rectification circuit are applied to perform delayed and/or instantaneous tripping functions and delivering, with or without a time delay, a circuit breaker tripping order when preset thresholds are exceeded by the signals representative of the currents flowing through the conductors or by the zero sequence signal, wherein the detection and rectification circuit comprises a group of diodes associated with each current sensor, each group comprising a first and a second diode arranged in series and whose common point is connected to a first output of the associated current sensor, a third and a fourth diode arranged in series and whose common point is connected to a second output of the associated current sensor, the anodes of the second and fourth diodes being connected and their common point connected to a first conductor constituting the negative output potential of the detection and rectification circuit, the cathodes of the first diodes of the different groups being connected to a second conductor and the cathodes of the third diodes of the different groups being connected to a third conductor distinct from the second, and means effecting the difference between the currents flowing through the second and third conductors, respectively constituting a first signal representative of the sum of the positive half-waves of the output signals from the set of current sensors and a second signal representative, in absolute value, of the sum of the negative half-waves of the output signals from the set of current sensors, so as to produce said zero sequence signal. - View Dependent Claims (3, 4, 5, 6, 7)
-
Specification