1. A protection system for a power distribution system comprising:
a bus voltage sensing unit configured to measure a bus voltage or a load voltage;
a demand response module for estimating available demand resources on the distribution system for a period of interest;
a distribution system analyzer for analyzing the bus voltage or the load voltage and system parameters to obtain voltage trip points for the available demand resources; and
a load control circuit to control the available demand resources based on the voltage trip points.
2. The protection system of claim 1, wherein the voltage sensing unit comprises a voltmeter or a potential transformer with a voltmeter or a processor that executes a load flow algorithm.
3. The protection system of claim 1, wherein the demand response module comprises a critical peak pricing (CPP) program, a variable peak pricing (VPP) program or a direct load control (DLC) program.
4. The protection system of claim 1, wherein system parameters include voltage regulator information, capacitor bank information, and adaptive relay settings.
5. The protection system of claim 1, wherein voltage trip points are voltage values associated with respective clearing times that determine on and off times for the available demand resources.
6. The protection system of claim 1, wherein controlling the available demand resources comprises switching on or off part or all of the demand resources.
7. The protection system of claim 1, wherein the voltage trip points are set to be faster than relay settings of current and voltage relays of the power distribution system.
8. The protection system of claim 1, wherein the distribution system analyzer obtains voltage trip points based on location of demand resources.
9. The protection system of claim 1, wherein the available demand resources includes demand resources on an adjacent bus.
10. The protection system of claim 1, wherein the distribution system analyzer further determines an amount of available demand resources that need to be utilized.
11. The protection system of claim 10, wherein the distribution system analyzer determines the amount of available demand resources based on sensitivity of bus voltage changes to power flow variations.
12. The protection system of claim 1, wherein the load control circuit sheds parts of the available demand resources selectively in steps.
13. The protection system of claim 1, wherein the distribution system analyzer is implemented in a centralized or a distributed manner.
14. A method of protecting a power distribution system comprising:
estimating available demand resources on the distribution system for a period of interest based on demand response programs;
establishing voltage trip points for the available demand resources based on bus voltages or load voltages and system parameters; and
controlling the available demand resources based on voltage trip points.
15. The method of claim 14, wherein the demand response programs include a critical peak pricing (CPP) program, a variable peak pricing (VPP) program or a direct load control (DLC) program.
16. The method of claim 14, wherein system parameters include voltage regulator information, capacitor bank information, and adaptive relay settings.
17. The method of claim 14, wherein controlling the available demand resources comprises switching on or switching off part or all of the demand resources.
18. The method of claim 14, wherein controlling the available demand resources comprises switching on or switching off parts of the available demand resources selectively in steps.
19. The method of claim 14, wherein the voltage trip points are set to be faster than relay settings of current and voltage relays of the power distribution system.
20. The method of claim 14, wherein estimating available demand resources on the distribution system comprises determining demand resources based on sensitivity of bus voltage changes to power flow variations.
21. The method of claim 14 further comprising establishing relay setting for protection relays of the power distribution system to detect high impedance fault.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A power plant, comprising:
an AC generator;
an AC-to-DC converter coupled to the AC generator and a DC bus;
a switch coupled to the DC bus; and
an active power compensation system coupled to the switch, wherein the active power compensation system reduces power load variations in the power plant.
2. The power plant of claim 1, in which the switch comprises a DC-to-DC converter.
3. The power plant of claim 1, in which the active power compensation system comprises power consumption devices to consume power when a load on the power plant decreases.
4. The power plant of claim 3, in which the power consumption devices are resistors.
5. The power plant of claim 3, in which the active power compensation system further comprises at least one energy storage device to provide energy when the load on the power plant increases.
6. The power plant of claim 5, in which the at least one energy storage device comprises at least one of an ultracapacitor, a capacitor, a battery, and a fly wheel.
7. The power plant of claim 6, in which the at least one energy storage device is coupled to one or more microcontrollers, wherein the one or more microcontrollers regulate the at least one energy storage device.
8. A method of reducing variations in a power load on a generator in a power plant, comprising:
routing power between the generator and at least one power consuming device during a time when the power load on the generator is lower than a first level to maintain a substantially constant power output of the generator.
9. The method of claim 8, in which the at least one power consuming device comprises at least one of a resistive element, variable resistive element, and a water break.
10. The method of claim 8, in which the first level is based, in part, on a fuel efficiency of the generator.
11. A method of reducing variations in a power load on a generator in a power plant, comprising:
routing power between an energy storage device and the generator during a time when the power load on the generator is higher than a first level, wherein the energy storage device provides energy to the power plant to maintain a substantially constant power output of the generator.
12. The method of claim 11, in which the energy storage device comprises at least one of an ultracapacitor, a capacitor, a battery, and a fly wheel.
13. The method of claim 11, in which the first level is based, in part, on a fuel efficiency of the generator.
14. The method of claim 11, further comprising:
routing power between the generator and the energy storage device during a time when the power load on the power plant is lower than a second level, wherein the second level is lower than the first level, and wherein the energy storage device stores energy from the power plant to maintain a substantially constant power output of the generator.
15. The method of claim 14, in which the second level is chosen, in part, based on a fuel efficiency of the generator.
16. The method of claim 14, further comprising:
routing power between the generator and a power consuming device during a time when an energy capacity of the energy storage device is substantially full.
17. A power plant, comprising:
means for generating power to meet a power load of the power plant; and
means for reducing variation in the power load of the power plant.
18. The power plant of claim 17, in which the reducing variation means comprises means for consuming power.
19. The power plant of claim 18, in which the reducing variation means further comprises means for storing energy.