In a traditional power grid system, the operator had total control of generation and distribution assets while the load was viewed as a disturbance. Thus, planning and operation necessitated always being prepared for unforeseen changes in the load consumption. The result is that the US power grid is amazingly resilient, robust, and expensive. As we consider a new paradigm of dc microgrid systems, overcapacity may not be feasible for technological and/or economic reason. Yet, high power quality and availability is more important than ever particularly to support the digital economy and information age. This is compounded as renewable sources become increasingly utilized, and the system operator no longer has total and arbitrary control of the generation. In this chapter, we introduced a framework for load control in a LAPES. In this paradigm, the load is considered to be an energy asset which can be controlled not just by the end user but also by the system. As such, a new degree of freedom is introduced in the control problem of balancing electrical supply and demand. Key to implementing any of these concepts is to strike the balance between the opportunity and cost, which would provide the techno-economic trade-off needed to implement these concepts practically. Important application-specific design considerations are the desired energy availability and the price willing to be paid for that availability as well as the tolerable amount of control relinquished. Optimizing this is not straightforward and may lead to solutions that change with time and conditions. To anticipate this, the chapter discussed the concept of load prioritization and a method to change the allowable control of the load.

Chapter Contents:

• 7.1 Introduction
• 7.1.1 Local area power and energy system
• 7.2 Why control the load?
• 7.2.1 Benefit of load control
• 7.2.2 Is load modulation practical?
• 7.3 Time-scale of energy requirements
• 7.3.1 Short-term transients
• 7.3.2 Long-term transients
• 7.4 Autonomous load control
• 7.4.1 Control
• 7.4.2 Architecture
• 7.4.3 Strategy for controlling the load to be an energy asset
• 7.5 Droop control for stability and information communication
• 7.5.1 Constant power load and its deleterious effect on dc systems
• 7.5.2 Steady state stabilization
• 7.5.3 Dynamic stabilization
• 7.6 Voltage-based load interruption
• 7.6.1 Power flow analysis
• 7.6.2 Contingency analysis
• 7.6.3 Search algorithm
• 7.7 dv/dt-Based dynamic load interruptions
• 7.8 Load prioritization and scheduling
• 7.9 Summary
• Acknowledgments
• References

Inspec keywords: power system economics; demand side management; power grids; power control; power consumption; distributed power generation; load regulation

Other keywords: application-specific design; power grid system; local area power and energy system; DC microgrids; energy availability; electrical supply demand; techno-economic trade-off; load consumption; LAPES; price willing; load control; load prioritization; controllable energy asset

Subjects: Control of electric power systems; Power system control; Power and energy control; Distributed power generation; Power system management, operation and economics