Apparatus for controlling opening and closing timings of a switching device in an electric power system

An apparatus for controlling a switching device provided for breaking or closing a power line connecting a power source to a load in an electric power system, said apparatus comprising:

• means for detecting whether said load is capacitive or inductive;
• switching timing control means responsive to a closing command externally applied thereto for applying a closing signal to said switching device at a timing which is controlled so that contacts of said switching device will be closed when a voltage of said power source attains a value which varies depending on whether said load is capacitive or inductive;
• and
• operating means for operating said switching device in response to said closing signal.

An apparatus for controlling a switching device provided for breaking or closing a power line connecting a power source to a load in an electric power system, said apparatus comprising:

• means for detecting whether said load is capacitive or inductive;
• switching timing control means responsive to a breaking command externally applied thereto for applying a breaking signal to said switching device at a timing which is controlled so that contacts of said switching device will be opened during a 1/4 cycle from a zero value to a peak value of a load current flowing through said power line and for applying a closing signal to said switching device at a timing which is controlled so that the contacts of said switching device will be closed when a voltage of said power source attains a value which varies depending on whether said load is capacitive or inductive;
• and
• operating means for operating said switching device in response to said breaking and closing signals.

An apparatus for controlling an integral three-phase switching device including three circuit breakers which are connected, respectively, in three phases of a power line connecting a power source to a load in a three-phase electric power system and are operated by a common operating unit, wherein said circuit breakers close successively at predetermined time intervals when operated by said common operating unit in response to a closing command externally applied thereto, said apparatus comprising:

• means for detecting whether said load is capacitive or inductive;
• means for applying a closing signal for closing said circuit breakers to said common operating unit in response to said closing command;
• and
• switching timing control means for controlling the timing at which said closing signal is applied to said common operating unit so that contacts of one of said circuit breakers which is to be closed first will be closed when a voltage of one phase of the three phases in which said one circuit breaker is connected attains a value which varies depending on whether said load is capacitive or inductive.

An apparatus for controlling an integral three-phase switching device including three circuit breakers which are connected, respectively, in three phases of a power line connecting a power source to a load in a three-phase electric power system and are operated by a common operating unit, wherein two of said circuit breakers close substantially at the same time when operated by said common operating unit in response to a closing command externally applied thereto, and the remaining circuit breaker closes after a predetermined time delay from the closing of said two circuit breakers, said apparatus comprising:

• means for detecting whether said load is capacitive or inductive;
• means for applying a closing signal to said common operating unit for closing said switching device in response to said closing command;
• and
• switching timing control means for controlling the timing at which said closing signal is applied to said common operating unit so that said two circuit breakers will be closed in response to said closing command when a voltage between two phases of the three phases in which said two circuit breakers are connected attains a value which varies depending on whether said load is capacitive or inductive.