Method and apparatus for controlling electrical loads
First Claim
1. In an electrical system including a load controller having a plurality of load controlling outputs each capable of assuming either a load-on condition or a load-off condition, said outputs being adapted for individually controlling the connections of a corresponding plurality of electrical loads to a power source, and a load regulating means connected to said controller for regulating the collective status of said load-on and load-off conditions at said outputs, said regulating means assuming an add mode when the number of said outputs that are in said load-on condition is to be increased and assuming a shed mode when the number of said outputs that are in said load-on condition is to be decreased, the improvement in said controller comprising:
- switching means connected to said outputs and having input means responsive to said regulating means for successively switching said outputs from said load-off conditions to said load-on conditions when the regulating means is in the add mode and for successively switching said outputs from said load-on conditions to said load-off conditions when said regulating means is in the shed mode, said switching means including means for establishing a plurality of different orders of succession in which said outputs are successively switched;
rotation circuit means for changing said switching means from one of said orders of succession to another of said orders of succession; and
,means for sensing a predetermined collective status of said conditions at said outputs, said rotation circuit means being operative in response to said means for sensing so as to change said switching means from one of said orders of succession to another of said orders of succession when said conditions at said outputs assume said predetermined collective status.
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Accused Products
Abstract
In an electrical load control system, method and apparatus are provided for selectively, individually connecting and disconnecting a plurality of loads to and from a power source. The loads are selectively connected (added), disconnected (shed), and reconnected (restored or added), in a predetermined sequence, wherein the ranking of the loads in such sequence is selectively rotated in a manner which results in a sharing of on and off time and an equalizing of wear among all of the loads. As an example of this operation, a load control system is disclosed in which the consumption of electrical power is varied by periodically shedding and adding individual loads in order to maintain the level of power usage below predetermined limits and yet make full use of the available power within such limits. For this purpose, a load regulating circuit monitors the power consumption and issues either an add command signal causing one or more loads to be connected, or issues shed command signal causing one or more of the loads to be disconnected, that is, shed. To uniformly distribute the off time associated with shed loads among all the loads, a load switching circuit means and a load rotation circuit means are provided for rotating the order in which the loads are shed, and thereafter restored or added. The rotation takes two forms. First, the order or rank in which the plurality of loads are shed, is shifted or rotated after each occurrence of a condition in which all of the loads have been turned on. Secondly, when less than all of the loads are on, the on-off ranking or status of the loads, resulting from the preceding add or shed command, is periodically shifted or rotated among all of the loads, in order to share the available electrical power on a timed rotation basis. Thus, the disruption of load service due to the curtailed power, is time shared among all of the loads on an equal, non-priority basis.
68 Citations
13 Claims
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1. In an electrical system including a load controller having a plurality of load controlling outputs each capable of assuming either a load-on condition or a load-off condition, said outputs being adapted for individually controlling the connections of a corresponding plurality of electrical loads to a power source, and a load regulating means connected to said controller for regulating the collective status of said load-on and load-off conditions at said outputs, said regulating means assuming an add mode when the number of said outputs that are in said load-on condition is to be increased and assuming a shed mode when the number of said outputs that are in said load-on condition is to be decreased, the improvement in said controller comprising:
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switching means connected to said outputs and having input means responsive to said regulating means for successively switching said outputs from said load-off conditions to said load-on conditions when the regulating means is in the add mode and for successively switching said outputs from said load-on conditions to said load-off conditions when said regulating means is in the shed mode, said switching means including means for establishing a plurality of different orders of succession in which said outputs are successively switched; rotation circuit means for changing said switching means from one of said orders of succession to another of said orders of succession; and
,means for sensing a predetermined collective status of said conditions at said outputs, said rotation circuit means being operative in response to said means for sensing so as to change said switching means from one of said orders of succession to another of said orders of succession when said conditions at said outputs assume said predetermined collective status. - View Dependent Claims (2, 3)
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4. In an electrical system including a load controller having a plurality of load controlling outputs each capable of assuming either a load-on condition or a load-off condition, said outputs being adapted for individually controlling the connections of a corresponding plurality of electrical loads to a power source, and a load regulating means connected to the controller for regulating the collective status of the load-on and load-off conditions of said outputs by assuming an add mode to increase the number of said outputs that are in the load-on condition and by assuming a shed mode to decrease the number of said outputs that are in the load-on condition, the improvement in said controller comprising:
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switching means connected to said load controlling outputs and having input means responsive to said regulating means for successively switching said outputs from said load-off condition to said load-on condition when the regulating means is in the add mode and for successively switching said outputs from the load-on condition to the load-off condition when the regulating means is in the shed mode; means for sensing the number of said outputs that are in the load-on condition; and rotation circuit means for rotating the load-on and load-off conditions among said outputs without changing the number of said outputs that are in the load-on condition, said rotation circuit means including timing means responsive to said means for effecting such rotation of the load-on and load-off conditions at a frequency that is dependent on the number of said outputs that are in the load-on condition. - View Dependent Claims (5, 6, 7)
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8. In a method of controlling the on-off conditions of a plurality of loads including the step of switching the loads in succession between on and off conditions for regulating the number of loads that are in the on condition in response to a regulating means that assumes an add mode when the number of on loads is to be increased and assumes a shed mode when the number of on loads is to be decreased, the steps in combination therewith comprising:
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switching the loads in succession from their off conditions to their on conditions when the regulating means is in its add mode and switching the loads in succession from their on conditions to their off conditions when the regulating means is in its shed mode, the steps of successively switching the loads being in accordance with one of a plurality of predetermined orders of succession; sensing a predetermined collective status of the on and off conditions of said plurality of loads; and automatically rotating the order in which said loads are successively switched between the on and off conditions from said one of a plurality of predetermined orders to another of such orders in response to said step of sensing said predetermined collective status. - View Dependent Claims (9)
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10. In a method of controlling the on-off conditions of a plurality of loads including the step of switching the loads in succession between on and off conditions for regulating the number of loads that are in the on condition, the steps in combination therewith comprising:
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sensing the number of loads that are in the on condition out of said plurality of loads; rotating the on and off conditions of said plurality of loads without changing the number of loads that are in the on conditions; and varying said time intervals as a function of said step of sensing the number. - View Dependent Claims (11)
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12. An electrical load control system for controlling the connections of a plurality of loads to a source of electrical power comprising:
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a load regulating means and a load controller means, said load controller means including switching means having input means and having a plurality of outputs, each of said outputs having a load-on condition and a load-off condition for controlling the connection of a separate one of the loads to the source of electrical power, said switching means being operative in response to receipt by said input means of a succession of add signals to successively switch said outputs from said load-off conditions to said load-on conditions, and being operative in response to receipt by said input means of a succession of shed signals to successively switch said outputs from said load-on conditions to said load-off conditions; said load controller means having a load status signal producing means for producing a load status signal representing the number of said outputs that are in said load-on condition; said load regulating means having difference signal producing means for producing a difference signal representing a predetermined difference relationship between a measured rate of power as it is consumed by those loads that are connected to the source of electrical power and a reference rate; said load controller means further having means for generating said add and shed signals that includes comparator means for comparing said difference signal with said load status signal, said comparator means causing the generation of at least one of said add signals when said difference signal and said load status signal have a first predetermined relation, and said load status signal changing each time one of the loads is connected in response to such a generated add signal so that said difference signal must also change before said first predetermined relation can again exist, and said comparator means causing the generation of at least one of said shed signals when said difference signal and said load status signal have a second predetermined relation, and said load status signal changing each time one of the loads is disconnected in response to such a generated shed signal so that said difference signal must also change before said second predetermined relation can again exist. - View Dependent Claims (13)
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Specification