Application of High-efficiency and Energy-saving Motors in Power Plants

1. The main principle and energy-saving effect of energy-efficient motors

A high-efficiency energy-saving motor, literally explained, is a general-purpose standard motor with high efficiency value. It adopts new motor design, new technology and new materials, and improves output efficiency by reducing the loss of electromagnetic energy, thermal energy and mechanical energy; that is, effective output A motor whose power is a higher percentage of the input power. Compared with standard motors, high-efficiency and energy-saving motors have obvious energy-saving effects. Normally, the efficiency can be increased by an average of 4%; the total loss is reduced by more than 20% compared with ordinary standard series motors, and the energy is saved by more than 15%. Taking a 55-kilowatt motor as an example, a high-efficiency and energy-saving motor saves 15% of electricity compared to a general motor. The electricity cost is calculated at 0.5 yuan per kilowatt hour. The cost of replacing the motor can be recovered by saving electricity within two years of using energy-saving motors.

Compared with standard motors, the main advantages of high-efficiency and energy-saving motors in use are:
(1) High efficiency and good energy-saving effect; adding a driver can achieve soft start, soft stop, and stepless speed regulation, and the power saving effect is further improved.
(2) The stable operation time of the equipment or device becomes longer, and the economic efficiency of the product is improved;
(3) Because the design of reducing loss is adopted, the temperature rise is small, thereby prolonging the service life of the equipment and improving the reliability of the equipment;
(4) Greatly Reduce environmental pollution;
(5) The power factor of the motor is close to 1, and the quality factor of the power grid is improved;
(6) There is no need to add a power factor compensator, the motor current is small, the transmission and distribution capacity is saved, and the overall operating life of the system is extended.

2. The main function and selection conditions of high-efficiency energy-saving motors in power plants

power plants are responsible for most of the power supply tasks in the country. At the same time, the production process of power plants is completely mechanized and automated. It requires many machines driven by motors to serve as its main and auxiliary equipment, so it is a large consumer of electrical energy. At present, the competition in the power industry is very fierce, but the key is the competition in manufacturing costs, so the work of reducing consumption and increasing efficiency is extremely important. There are three main economic and technical indicators for generator sets: power generation, coal consumption for power supply, and power consumption. These indicators are all related to each other and affect each other. For example, a 1% change in the factory power consumption rate has an impact coefficient of 3.499% on the coal consumption for power supply, and a 1% drop in the load rate affects the factory power consumption rate to increase by 0.06 percentage points. With the installed capacity of 1000MW, if it is operated under the rated operating conditions, the factory power consumption rate is calculated at 4.2%, the capacity of the factory power consumption will reach 50.4MW, and the annual electricity consumption is about 30240×104kW.h; if the power consumption A reduction of 5% can save about 160MW.h of electricity consumed by the plant every year. Calculated at an average on-grid electricity price of 0.35 yuan/kW.h, it can increase the income of electricity sales by more than 5.3 million yuan, and the economic benefits are very obvious. From a macro perspective, if the average power consumption rate of thermal power plants decreases, it will relieve the pressure on resource shortage and environmental protection, improve the economic efficiency of thermal power plants, curb the increasing power consumption rate, and ensure the sustainable development of my country’s national economy. Has important meaning.

Although high-efficiency motors are more efficient than standard motors, in terms of cost and manufacturing cost, under the same circumstances, the price of high-efficiency motors will be 30% higher than ordinary motors, which will inevitably increase the initial investment of the project. Although the price is higher than that of ordinary Y series motors, considering the long-term operation, as long as the motor can be selected reasonably, the economy is still obvious. Therefore, in the selection and bidding of power plant auxiliary equipment, it is necessary to select the appropriate equipment with a target and use high-efficiency energy-saving motors.

Process professional has done a lot of optimization, canceled the electric feed water pump; the electric induced draft fan was cancelled and used the steam driven induced draft fan to drive; but there are still many high-voltage motors as the driving device of the main equipment such as water pumps, fans, compressors, and belt conveyors. Therefore, it is recommended to assess and select the motor energy consumption and efficiency of auxiliary equipment from the following three aspects to obtain large economic benefits.

Post time: Jul-01-2021