1. Project overview
The Hami Power Plant 4 × 660MW project is one of the first supporting power sources for the ± 800 kV ultra-high voltage direct current transmission and distribution project from Hami to Zhengzhou. The power plant is located adjacent to the No.1 mine in the Danianhu mining area of Hami, which is owned by State Grid Energy Hami Coal and Electricity Co., Ltd. The project adopts the construction model of a coal electricity integrated pithead power plant. Coal is directly transported into the plant by a belt, which can achieve on-site resource conversion and convert coal into power transmission, in line with national energy industry policies. At the same time, the construction of this project can connect Xinjiang, which accounts for one sixth of the total area of the country, to the Northwest Power Grid, thereby achieving a true national power grid and optimizing resource allocation on a larger scale. It also conforms to the overall energy flow trend of China's "West East Power Transmission, North Coal South Transmission, and North Power South Transmission".
2. Overview of working conditions
The direct air cooling system for the 3 # and 4 # units of the 4 × 660MW project in Hami Power Plant consists of 8 rows of direct air-cooled condenser systems (ACC), each with 8 fan units (1 fan per unit), totaling 64 fan units. Each fan is controlled by a frequency converter to regulate the fan speed and control the turbine exhaust pressure at the set value. As a typical nonlinear load, frequency converters generate high-order harmonic currents during operation, leading to excessive harmonic voltage and current in the power supply system, resulting in poor power quality and seriously affecting system reliability and stability.
In order to improve the efficiency of power supply for factory use, reduce the non application capacity of the power supply, and effectively eliminate long-term harmonic pollution caused by the frequency converter, the SFRPF series active power filter is selected to filter out the harmonic voltage and current generated during the operation of the frequency converter.
3. Measurement data
Comparison of harmonic data in the power grid before and after the operation of active power filters:
4. Waveform diagram
Comparison of waveforms before and after the operation of active power filters:
5. Introduction to SFERE series active power filter functions
Active power filter is a new type of power electronic device used for dynamic filtering of harmonics and compensating reactive power. It can filter and compensate for harmonics (both in size and frequency) and dynamic reactive power in real time, overcoming the shortcomings of traditional harmonic suppression and reactive power compensation methods such as traditional filters. It realizes the harmonic filtering function and reactive power compensation function of the system, and is widely used in power, metallurgy, petroleum, ports, chemical and mining enterprises, etc.
1. Real time display
Real time measurement data: voltage and current of power supply and load, total harmonic voltage distortion rate (THDU), total harmonic current distortion rate (THDI), each harmonic (THIn), power, power factor, waveform of each phase, harmonic bar graph, switch state, etc.
2. Event recording
Can query the operator's records of various operations on the filter, such as turning on, off, setting parameters, etc; It can display alarm information in real-time and provide historical alarm record queries, with 500 cyclic displays and a regular fault help menu, making it convenient for maintenance personnel to quickly diagnose faults.
3. Performance indicators
Filter frequency selection: 2-50 times optional; Full response time: less than 5ms; Target power factor: adjustable from -1 to 1; Switching frequency: 20kHz; Noise index:<65DB; Overall efficiency: greater than 97%.
Partial display interface:
6. Project summary
The expected goals have been achieved, and the harmonic voltage and harmonic current distortion rate at the incoming cabinets of each transformer have met the requirements of the national standard GB/T 14549, purifying the electrical environment, ensuring the safe and stable operation of equipment, and greatly improving the effective utilization rate of electrical energy; Reduced distribution line losses, increased terminal voltage, and extended service life of cables and equipment.
