摘要:
A device for operating a relay to selectively provide power from a power supply to a load. The device determines an activation switching point for activating the relay such that inrush current resulting from the activation is minimal. The device also determines a deactivation switching point for deactivating the relay such that backrush current is minimal. The switching points are determined with respect to a voltage waveform of the supply power. The device varies the timing of the operation of the relay with respect to the voltage waveform and monitors the inrush or backrush current resulting from each timing until a minimum inrush or backrush current is found. The device stores these times in memory for subsequent operation of the relay. To further reduce inrush and backrush currents associated with inductive loads, the device activates and deactivate the relay on opposite half cycles.
摘要:
Circuitry, systems and methods that address the need to coordinate relay switching with another event, such as a zero crossing of an alternating current (AC) voltage waveform are described. In some embodiments, the systems and methods continuously or periodically calibrate the timing of control signals to a relay, such that the switching of the relay in response to some (e.g., second or subsequent) control signals occurs closer in time to a zero crossing of an AC line voltage than the switching of the relay in response to other (e.g., initial or first) control signals.
摘要:
A method of controlling the opening or the closing of an AC electric circuit in an electricity meter by means of a relay is provided. The method times relay activation commands so as to take account of the inertial delay (di) of the relay, in such a manner that the actual activation command applied to the relay causes the relay actually to take action on the electric circuit when an electrical parameter of said circuit reaches a zero value, in order to limit the formation of electric arcs in the relay.
摘要:
A switching controlgear of circuit breaker 100 outputs an opening command signal or closing command signal to the circuit breaker with the maximum being 1 cycle or less of wait time when the opening command signal or closing command signal is detected, and can cause the circuit breaker to open or to close at a desired phase of the main circuit current or power system voltage. The switching controlgear of circuit breaker 100 has switching control signal output time calculation means 10 and switching command signal output delay means 20. The switching control signal output time calculation means 10 calculates the switching control signal output time using the detection timing of the opening command signal or closing command signal as a reference so that the circuit breaker opens or closes at the desired phase after the total time of the switching control signal output time and the estimated opening operation time or estimated closing operation time of the circuit breaker 620 is elapsed. The switching command signal output delay means 20 outputs a delay-controlled opening command signal or a delay-controlled closing command signal to the circuit breaker after the switching control signal output time, which is the latest, is elapsed when an opening command signal or closing command signal is actually detected.
摘要:
Various systems and methods are provided for minimizing an inrush current to a load after a voltage sag in a power voltage. In one embodiment, a method is provided comprising the steps of applying a power voltage to a load, and detecting a sag in the power voltage during steady-state operation of the load. The method includes the steps of adding an impedance to the load upon detection of the sag in the power voltage, and removing the impedance from the load when the power voltage has reached a predefined point in the power voltage cycle after the power voltage has returned to a nominal voltage.
摘要:
Various systems and methods are provided for minimizing an inrush current to a load after a voltage sag in a power voltage. In one embodiment, a method is provided comprising the steps of applying a power voltage to a load, and detecting a sag in the power voltage during steady-state operation of the load. The method includes the steps of adding an impedance to the load upon detection of the sag in the power voltage, and removing the impedance from the load when the power voltage has reached a predefined point in the power voltage cycle after the power voltage has returned to a nominal voltage.
摘要:
The system of the invention includes a circuit breaker switching control section (100) and a setting control section (700) connected therewith through a communication network (500). The circuit breaker switching control section (100) transmits a circuit breaker state quantity acquired by a signal input section (120) through the communication network to a set value calculation section (740) of the setting control section (700). The set value calculation section (740) of the setting control section calculates a set value to be set in the switching control section (100) of the circuit breaker, using the state quantity of the circuit breaker that was transmitted thereto. The setting control section (700) transmits to the circuit breaker switching control section the set value calculated by the set value calculation section (730) through the communication network. A switching control calculation processing section (140) provided in the switching control section of the circuit breaker corrects the circuit breaker switching actuation time in accordance with this set value and calculates a delay time in respect of the zero-cross point in accordance with this corrected switching actuation time and power system period.
摘要:
Assemblies, systems, and methods which prolong relay life by dynamically compensating the make and break contact timing between the contact points of the relay and a zero crossing point of the power supply's waveform are provided according to the present disclosure. The life cycle of the relay components are dramatically increased through the use of these assemblies, systems, and methods due to a decrease in arcing and other physically damaging phenomena between the contacts of the relay. The present disclosure also provides for assemblies, systems, and methods whereby a processor analyzes the inductive kickback effect in the relay load voltage signal and dynamically adjust the relay open time such that the inductive kickback effect is minimized. In exemplary embodiments, the systems/methods provided herein advantageously adjust the relay open time such that the relay switching time corresponds with current zero cross and do so without requiring complicated current monitoring components.
摘要:
Various systems and methods are provided for minimizing an inrush current to a load after a voltage sag in a power voltage. In one embodiment, a method is provided comprising the steps of applying a power voltage (100) to a load (246), and detecting a sag in the power voltage (106) during steady-state operation of the load. The method includes the steps of adding an impedance (RT) to the load upon detection of the sag in the power voltage, and removing the impedance when the power voltage has reached a predetermined poin in the power voltage cycle after the voltage has returned to normal.
摘要:
A switchgear control apparatus includes a zero point interval detecting circuit, an interruption time judgment circuit and a reclosing time decision circuit. The zero point interval detecting circuit detects time intervals between successive zero points of a main circuit current. The interruption time judgment circuit judges that interruption time of the main circuit current is time of a zero point immediately preceding a zero point at which a difference between the time interval between two successive zero points and half the period of a commercial AC voltage exceeds a specific value. Upon detecting the gradient of the main circuit current at the interruption time, the reclosing time decision circuit sets reclosing time at a point in phase where the AC voltage has a maximum negative value if the gradient is positive, and at a point in phase where the AC voltage has a maximum positive value if the gradient is negative.