P3. Smart Load Control and Grid-Friendly Appliances > Conclusions

The two control approaches investigated were not successful in detecting grid stress.

Commercialization potential:

The two approaches investigated should not be commercialized. Other approaches discussed under the Recommendations section may have better promise.

Recommendations:

With the insights gained from the simulation and data analysis, the following recommendations for additional research are made:

• Under-frequency load control could provide an important grid reliability enhancement. Although reactive in its response, an under-frequency load control strategy with frequency responsive appliances and devices could provide reserves that are currently furnished by generators that are either already spinning or that can be ramped up in their output.

• To enhance fundamental understanding of the stability characteristics of the power system, it is recommended that system identification techniques be used to approximate a real-time transfer function of the entire power system. If a real-time system transfer function of sufficient accuracy can be established, it would enable the use of standard stability analysis tools for determining distance to the stability edge.

• For dealing with voltage stability problems, we recommend the use of under-voltage relays of induction motors, as found in compressor motors for air-conditioning systems and other appliances. The under-voltage protection prevents motor stalling caused by decreasing voltage as a result of a line fault or high system loading. The stalling of induction motors perpetuates the decreasing voltage to a point, where the voltage may drop sharply and quickly and propagate through the distribution systems as other electric motors reach the same conditions.

Benefits to California:

Based on new data regarding the characteristics of California building stock and statewide energy use, the projected benefits of this project are updated as follows:

Updated Baseline:

The residential load in Year 2000 was 80,758 GWh/yr.

Updated Outcome:

The approach investigated will not detect grid stress conditions as defined during the project research. Consequently, no savings are available from this approach.

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