Pre-reform background
Yaoming Power Plant, Pingdingshan Yaomeng Power Generation Co., Ltd. has 6 generators: Units 1 to 4 are 300MW coal-fired units, and No. 3 and 2 induced draft fans (2000KW/6KV) were implemented by Leader Huafu in 2009. Transformation. After the transformation, the equipment was in good operation, with few failures. The power-saving effect was very satisfactory, and the customer's recognition of the Leader Hua Fu brand was enhanced.
Units 5-6 are 600 MW coal-fired units, originally four 3800 KW/6KV induced draft fans. In response to the national emission reduction requirements in 2012, the denitrification renovation was carried out, and the induced draft fan was expanded to 4400 KW/6KV, and the transformation of frequency conversion regulation was also increased. So far, Leader Huafu has applied many high-power fan loads. Users have full confidence in our technical strength, manufacturing process, and equipment quality.
The induced draft fan is one of the key loads of the power plant. Its main function is to extract the flue gas from the boiler, thereby maintaining the negative pressure of the furnace, forming a flowing flue gas in the flue, completing the heat exchange between the flue gas and the air, and denitrification of the flue gas. Process. Due to the reasons such as peaking of the power grid and changes in the load of the power grid system, most of the power generation load of the power plant cannot reach full-load operation, which brings about huge space for the energy conservation of the induced draft fan. As the key equipment of the wind smoke system, the induced draft fan is frequently adjusted with the fluctuation of the load. It also needs a more accurate and flexible adjustment method to meet the changes of the on-site working conditions. Therefore, it is imperative that Yaomei Power Plant's induced draft unit reforms the frequency conversion, and it is determined that Lide Huafu's brand will be used to retrofit four induced draft fans.
Frequency conversion program
Main loop scheme: The two induced draft fans of one unit are all in the main loop mode with one tow and one automatic bypass. Due to their large rated current (520A), the automatic bypass consists of three switchgears and the complete system is provided by us. The company provides three Schneider circuit breakers for its use. Although automatic bypass is used, due to the consideration of system and motor safety, when the inverter fails, it does not use the function of automatically switching to the power frequency, but is to be checked on site. After completion, it is allowed to start running at the power frequency.
System operation mode: The site is operated by two induced draft fans in parallel, and DCS performs closed-loop control according to the negative pressure of the furnace. The setting value of the furnace negative pressure is -20 pa and the inlet draft pressure of the induced draft fan is -3.15 Kpa.
Installation and cooling methods: The power plant has limited on-site space. The two units of a unit are placed in one room. The layout is relatively compact, back-to-back, and the indoor space is fully utilized. Indoor air-conditioning cooling, the power plant originally planned to use heat-insulated wall to separate the transformer cabinet and power unit cabinet heat, but because there is no air inlet in the site, the negative pressure of the transformer room is too large after the separate layout, so the user will eventually heat the wall The doors are open and all use air conditioning for cooling.
Equipment operation effect
The two units of the No. 5 machine of this project were formally put into operation last year, and the installation of two units of No. 6 was completed. The load of the unit is determined by the provincial dispatch. According to the needs of the peak load adjustment and the like, the fluctuation is relatively frequent, but most of the time it operates between 400,000 and 600,000 loads. Through the collection and comparison of field data, we can see that in the same 350,000 load case, the inverter current is about 60A, the power frequency current is about 140A, the inverter is about 30Hz, and the unit is 600,000 load, the inverter runs. The current is about 210A, the power frequency current is about 230A, and the inverter runs at about 35Hz. The average electricity saving rate is above 20%.
Frequency conversion reform conclusion:
1. Through the frequency conversion of 600MW induced draft fan at Yaomeng Power Plant, there is a practical demonstration significance for the future transformation of the 600MW unit: Leader Huafu is the most powerful to achieve safe and reliable operation of the larger power plants or important load of the unit. LeadHuafu high-voltage variable frequency speed control system allows you to enjoy worry-free operation.
2. The induced draft fan speed control method for large-capacity generator sets can fully adopt the scheme of frequency converter speed control, including the same after denitrification reform. This program can be applied to maximize the implementation of energy efficiency, and promote the value of the company.
3. In this project, when the unit is running at full load, the frequency conversion operating current is less than half of the rated current. It can be seen that the margin reserved by the induced draft fan is very large, and the energy-saving potential after the induced draft fan is transformed is also very large. Therefore, the prospect of frequency conversion transformation is very broad. It is our sacred mission to meet market demands and promote the development of enterprises.