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US 5,627,415 AGranted
System and method for opening/closing circuit breakers
AssigneeHydro-Quebec
InventorsClaude Charpentier, Raymond Rajotte
Life of this patent
Estimating the term…
Abstract
The first zero crossing of the power signal, after the detection of an opening/closing signal, initiates a series of predetermined, timed, steps which reduces or eliminates the overvoltage after opening/closing a circuit breaker on a high power line.
Claims12
A system for timing the opening and closing of a switching arrangement used in high power electrical transmission systems which transmit at least one phase of an AC power signal (A,B,C) comprising:
- phase angle detector means for detecting a phase of said power signal and for providing a phase indication signal;
- sensing means for sensing a temperature and controlling operation of said switching arrangement and producing a temperature signal;
- and
- control means connected to said phase detector means, and said sensing means for opening and closing said switching arrangement;
- switch means for providing an OPEN/CLOSE initiating signal for initiating the opening/closing of said switch arrangement;
- wherein
- said sensing means sense only ambient temperature;
- said control means are connected to said switch means and generate a switching arrangement opening and closing signal in response to said initiating signal timed as a function of said temperature signal and said phase indication signal;
- said control means include means for calculating t.sub.mo2 for different temperatures according to the formula:
- t.sub.mo2 =t.sub.mo1 -a.sub.o (T.sub.2 -T.sub.1)
- where
- a.sub.o is a value which is indicative of the sensitivity of the switching arrangement to temperature and is given by a manufacturer of the switching arrangement
- T.sub.2 is the ambient temperature
- T.sub.1 is a standard temperature
- t.sub.mo1 is a precalibrated switch opening time at said standard temperature
- t.sub.mo2 is a switch opening time at temperature T.sub.mo2 ;
- and
- said control means include means for calculating t.sub.mc for different temperatures according to the formula:
- t.sub.mc2 =t.sub.mc1 a.sub.c (T.sub.2 -T.sub.1)
- where
- a.sub.c =a value which is indicative of the sensitivity of the switching arrangement to temperature and is given by a manufacturer of the switching arrangement
- T.sub.2 =ambient temperature
- T.sub.1 =a standard temperature
- t.sub.mc1 =a precalibrated switch closing time at said standard temperature
- t.sub.mc2 =switch closing time at temperature T.sub.2.
22 more elements
A method for tinting the opening and closing of a switching arrangement used in high power electrical transmission systems which transmit at least one phase of a power signal having a sinusoidal variation, comprising:
- detecting a phase angle of said power signal and generating a phase indication signal;
- sensing ambient temperature only for controlling operation of said switching arrangement and producing a temperature signal;
- providing an OPEN/CLOSE initiating signal to initiate the opening/closing of said switching arrangment;
- generating a switching arrangement opening and closing signal in response to said initiating signal timed as a function of said temperature signal and said phase indication signal;
- and
- controlling opening and closing of said switching arrangement;
- wherein:
- said step of controlling further includes a step of calculating t.sub.mo2 for different temperatures according to the formula:
- t.sub.mo2 =t.sub.mo1 -a.sub.o (T.sub.2 -T.sub.1)
- where
- a.sub.o is a value which is indicative of the sensitivity of the switching arrangement to temperature and is given by a manufacturer of the switching arrangement
- T.sub.2 is an ambient temperature
- T.sub.1 is a standard temperature
- t.sub.mo1 is a precalibrated switch opening time at said standard temperature
- t.sub.mo2 is a switch opening time at T.sub.2, when controlling the opening of said switch arrangement;
- and
- said step of controlling further includes a step of calculating t.sub.mc2 for different temperatures according to the formula:
- t.sub.mc2 =t.sub.mc1 -a.sub.c (T.sub.2 -T.sub.1)
- where
- a.sub.c =a value which is indicative of the sensitivity of the switching arrangement to temperature and is given by a manufacturer of the switching arrangement
- T.sub.2 =ambient temperature
- T.sub.1 =a standard temperature
- t.sub.mc1 =a precalibrated switch closing time at said standard temperature
- t.sub.mc2 =a switch closing time at temperature T.sub.2.
21 more elements
Dependencies are inferred from the claim text.