To improve the cost efficiency of distributed resources, in a true sense, the low and medium voltage layers of traditional power systems are their own distributed resources. In particular, the low-voltage utility network is distributed in the service area, reaching each user, and its local size is proportional to the local user’s energy demand. However, “distributed resources” in modern power systems are only used for power systems, where electrical energy itself is produced by machinery, facilities or systems distributed throughout the service area, rather than concentrated in a few large central power stations Power plant production. Distributed resources include small generators, which include:
①Small low head hydroelectric unit;
② wind turbine;
③ Micro-turbine-driven generator set;
④High-speed and medium-speed diesel generator sets;
⑤ Photovoltaic modules;
⑥ Small solar thermal generator set.
These small generators are distributed throughout the utility service area and need not be proportional to user demand. For example, in a rural area, IMV.A’s wind turbines may be located in the farming area, 2 miles from the farmhouse and the harvesting/drying equipment that requires the most power. In urban areas, electricity produced by a 2MV.A PV module on an office roof can sometimes be sent miles away to serve nearby residential needs. But in general, these distributed generation resources usually have the following characteristics:
(1) Closer to energy users than to centralized power plants. Therefore, compared to the transmission of traditional systems, the power transmission cost of distributed generation resources may be lower, the transmission reliability is higher, the aesthetics of the transmission line is better, and the environmental impact is lower (fundamentally, all three points are Since the transmission path is shorter than that of the conventional power system).
(2) The overall unit cost efficiency of electric energy is lower than that of large centralized power plants. Profits can be large or small, depending on the specific technology and characteristics of each situation.
(3) The use and popularization of distributed resources relies on the economic, service quality, social and market advantages arising from proximity to users, as opposed to the disadvantage of lower potential power generation per unit of electricity production.
Demand response as a distributed resource. In some cases, distributed resources (DR) also include non-generating resources that can be dispatched like power generation. For example, demand response or load control, can shut down a certain load for a period of time to maintain a balance between system resources and demand. • Many system operating decisions aim to achieve and maintain this balance, and from this standpoint, the difference between increased generation or decreased demand is not large. Dispatchable load control, whether direct (appliances and equipment shut down by themselves) or indirect (slowly reduced feeder voltage, lowering the load on the connected load), the result is the same: at the request of the system operator, changes are made to help control the proportion of generation load.
In some cases, utility planners, managers, and regulators limit demand response to methods that are directly dispatchable (near real-time controllable) by the utility or system operator—methods such as direct load control or active demand limiters . In other cases, however, demand response involves procedural and load-influencing methods that rely on user or automated (user-programmed) price-sensitive responses to demand, such as real-time pricing (RTP) methods. These methods do not provide immediate direct load control—demand reduction takes seconds or minutes to be effective, or no effect at all—and users may override these methods in critical situations. As a result, their effect is uncertain, sometimes not accounting for distributed resources, but sometimes others accounting for demand response and distributed resources. It is best to require that ambiguity and confusion be avoided in all cases.