1. Load management measures
According to the load characteristics of the power system, load management is to reduce the power demand of users from the peak period of power grid load or transfer it to the low period of power grid load in some way, reduce the daily or seasonal peak load of power grid, promote the rational distribution of power demand in different time series, improve the utilization rate of equipment in the low period, and improve the reliability and economy of system operation. There are three kinds of load shaping: peak clipping, valley filling and peak shifting.
Figure 5.6 Main Contents of DSM
1) peak clipping
Peak load regulation is to reduce the power demand of users during the peak load of power grid, stabilize the system load and avoid tripping and power failure, which not only increases the satisfaction of users, but also avoids the new installed capacity with marginal cost higher than average cost and reduces the cost of power grid enterprises. However, on the other hand, cutting the summit will lead to the reduction of electricity sales during the peak period and reduce part of the income of power grid companies. Peak clipping is shown in Figure 5.7.
2) Grain filling
Valley-filling, also known as strategic load growth, refers to stimulating users to increase electricity consumption during low power grid hours through preferential electricity prices. This method is especially suitable for power systems with large peak-valley load difference, idle low-cost power generation capacity, poor low-load regulation capacity and piezoelectric difficulties, which is beneficial to start idle power generation capacity, reduce the average fuel cost of the system, and improve the economy of system operation and the stability of power grid load. Because of the increase of sales electricity, the fixed cost of unit electricity is reduced, the sales income of power grid companies is increased, and the enthusiasm of enterprises can be mobilized. Valley filling is shown in Figure 5.8.
The commonly used technical measures for valley filling include increasing the storage capacity and increasing the electric equipment used in low valleys.
3) peak shifting and valley filling
Shifting the peak and filling the valley is to dispatch the power side through the alternating operation of time-of-use electricity price and high-power equipment, and arrange part of the load in the peak load period to the low peak period, and at the same time play the dual role of cutting the peak and filling the valley. It can not only make full use of idle capacity and reduce newly installed capacity, but also stabilize system load and reduce power generation energy consumption. In the power system with serious power shortage, large peak-valley difference and limited load regulation ability, shifting peak and filling valley has always been a main task to improve power grid management. The peak shift and valley filling are shown in Figure 5.9.
Figure 5.7 Schematic diagram of peak clipping
Fig. 5.8 schematic diagram of valley filling
2. Energy efficiency management measures
Energy efficiency management refers to taking effective incentive measures, changing users' consumption behavior, adopting advanced energy-saving technologies and efficient equipment, and improving the efficiency of terminal electricity consumption. Its fundamental purpose is to save electricity and reduce electricity consumption. Energy efficiency management measures include direct power saving and indirect power saving. Direct power saving is achieved by adopting scientific management methods and advanced technical means, while indirect power saving is achieved by adjusting economic structure, improving product production efficiency, rationally distributing productivity and reducing the export of high energy-consuming products. The DSM based on energy efficiency can be simply represented by Figure 5. 10, and the whole load curve moves down, representing the decline of the whole electricity consumption. In order to encourage power users to adopt high-efficiency equipment, the government will generally give power users certain economic incentives, such as free installation, low-interest loans, preferential electricity prices and so on.
Figure 5.9 Schematic diagram of peak shifting and valley filling
Fig. 5. 10 schematic diagram of the influence of demand side management based on energy efficiency on load