Load shedding apparatus

Claim 2

Apparatus for automatically shedding load in a power distribution area in which a plurality of sources are connected to supply power to a plurality of loads comprising a first means operable to produce a signal representative of the magnitude of the prevailing reserve power of the area, and a second means operable to disconnect at least one of the loads of said area when said prevailing reserve power signal drops to a predetermined value.

Claim 3

Apparatus as set forth in claim 1 in which said first means includes means responsive to the power flow to or from the sources of the area for producing a first signal representative of the prevailing area load, means for producing a second signal representative of the total prevailing capability of said sources, and means for comparing said first and second signals to produce said signal representative of the prevailing reserve power.

Claim 4

means for producing a signal representative of the total prevailing capability of said sources, including; a. means for producing third signals respectively representative of the capability of each of said generating sources, b. means for producing fourth signals respectively representative of the capacity of each of said tie lines, and c. means for summing said third and fourth signals to produce said total prevailing capability signal; and

Claim 5

means for producing a signal representative of the total prevailing capability of said sources, including; a. means for producing third signals respectively representative of the capability of each of said generating sources, b. means for producing fourth signals respectively representative of the capacity of each of said tie lines, and c. means for summing said third and fourth signals to produce said total prevailing capability signal; and

Claim 6

means for comparing said prevailing area load signal and said total prevailing capability signal to produce said signal representative of the prevailing reserve power; and means operable to disconnect at least one of the loads of said area when said prevailing reserve power signal drops to a predetermined value.

Claim 7

means for comparing said prevailing area load signal and said total prevailing capability signal to produce said signal representative of the prevailing reserve power; and means operable to disconnect at least one of the loads of said area when said prevailing reserve power signal drops to a predetermined value.

Claim 8

Apparatus for automatically shedding load in a power distribution area in which a plurality of sources are connected to supply power to a plurality of loads, comprising: means operable to produce a signal representative of the magnitude of the prevailing reserve power of the area, including;

Claim 9

Apparatus for automatically shedding load in a power distribution area in which a plurality of sources are connected to supply power to a plurality of loads, comprising: means operable to produce a signal representative of the magnitude of the prevailing reserve power of the area, including;

Claim 10

Apparatus as set forth in claim 1 in which said second means includes means for producing for each portion of the load to be shed a margin setter signal representing the magnitude of prevailing reserve power at which the associated load should be shed, means for individually comparing each of said margin setter signals and said signal representing the prevailing reserve power, and means responsive to said last named means for disconnecting each of said loads when the signal representing the prevailing reserve power equals the associated margin setter signal.

Claim 11

Apparatus as set forth in claim 1 in which said first means includes means responsive to the power flow from said sources for producing a first signal representative of the total power flow to the loads of said area, means for producing a second signal representative of the total capability of saiD sources, means for producing a third signal representative of the preferred reserve power, and means for comparing the difference between the values of said first and second signals and the value of the third signal to produce a resultant signal representative of the prevailing area margin.

Claim 12

In a power distribution area having a plurality of sources providing power to a network to which a plurality of loads are connected, apparatus for selectively shedding said loads in accordance with pre-established priorities comprising transducer means associated with each of said sources for producing signals representative of the power being provided to said network from each of said sources, capability setter means each associated with one of said sources for producing capability signals each representative of the power producing capability of the associated source, means responsive to said power signals and said capability signals for producing a signal representative of the prevailing reserve power of said sources, means for producing a signal representative of the preferred reserve capability of said area, means for comparing the prevailing reserve power signal and the preferred reserve capability signal to produce a signal representative of the prevailing margin of the area, means for producing for each of the loads a margin setter signal representing the magnitude of the prevailing margin of the area at which the associated load is shed, comparison means for comparing each of said margin setter signals to the prevailing margin signal and operative when said last named signal decreases to the value of a margin setter signal to disconnect the associated load from the network when that load is next in priority to thereby avoid loading said area beyond the prevailing area margin while maintaining priorities in the shedding of said loads.

Claim 13

In a power distribution area having a plurality of sources providing power to a network to which a plurality of loads are connected, apparatus for selectively shedding said loads in accordance with pre-established priorities comprising transducer means associated with each of said sources for producing signals representative of the power being provided to said network from each of said sources, capability setter means each associated with one of said sources for producing capability signals each representative of the power producing capability of the associated source, means responsive to said power signals and said capability signals for producing a signal representative of the prevailing reserve power of said sources, means for producing a signal representative of the preferred reserve capability of said area, means for comparing the prevailing reserve power signal and the preferred reserve capability signal to produce a signal representative of the prevailing margin of the area, means for producing for each of the loads a margin setter signal representing the magnitude of the prevailing margin of the area at which the associated load is shed, comparison means for comparing each of said margin setter signals to the prevailing margin signal and operative when said last named signal decreases to the value of a margin setter signal to disconnect the associated load from the network when that load is next in priority to thereby avoid loading said area beyond the prevailing area margin while maintaining priorities in the shedding of said loads.

Claim 14

Apparatus as set forth in claim 6 which includes means operable to prevent the transducer means associated with those sources which are tie lines from producing signals which are of sense representative of power flow from said area over said tie lines.