1. Introduction With the development of technology, the degree of automation of business hotels is getting higher and higher, and there are more and more automatic control devices. The EIB intelligent lighting system has gradually become the standard configuration of high-end business hotels. At the same time, in order to save energy, the frequency converter is widely used in air conditioning systems and elevators. However, the above-mentioned equipment generates a large number of harmonics in the work. Taking the frequency converter as an example, there are both a rectifier and a high-frequency inverter, and a large number of harmonics are generated simultaneously in the high and low frequency bands. Harmonics have been combined with electromagnetic interference and power factor reduction as the three major public hazards of the power system. Therefore, the measurement and analysis of harmonics is an important task in power system analysis and control, and it is an important prerequisite for relay protection and fault measurement. 
3.2 ANAPF technical parameters 
2. Harm of harmonics in business hotels The non-linear load of business hotels generates high-order harmonics objectively. Because the amount of harmonics is too large, it will not only pollute the power supply grid, but also adversely affect the communication and power equipment of business hotels. .
2.1 Harm to the power supply grid The pollution caused to the power supply grid causes additional losses in the components of the power grid, reducing the use efficiency of power generation, power distribution and power equipment, and even causing the line to overheat and causing fire; due to the influence of harmonics in the current, the power grid The voltage also has an effect, so that the total harmonic distortion rate of the grid voltage also exceeds the national standard.
2.2 Hazards to the operation of business hotels (1) Adding additional losses to the equipment itself, affecting the normal operation of electrical equipment in business hotels, causing mechanical vibration, noise, over-voltage, causing overheating of transformers, capacitors, wires and other equipment, insulation aging, and shortened service life; (2) Interference to adjacent communication systems, which causes noise, reduces communication quality, and causes loss of information, making the communication system inoperable.
(3) Due to the logistics requirements of business hotels, the load starts and stops frequently, causing surges and transients in the power grid. The sudden change of voltage and current will cause overvoltage, which greatly shortens the life of electrical equipment and increases the investment cost of equipment.
(4) The current harmonic index is seriously exceeded, causing certain impact on the system such as EIB, often causing unplanned failure of the system.
3, business hotel harmonic solution To ensure the high reliability requirements of business hotels, in the design and construction stage, the following measures are mainly taken to prevent harmonic interference to the equipment.
(1) Design a dedicated loop for electronic equipment, and avoid harmonic interference along the power supply line as much as possible.
(2) Add line filters to susceptible devices to eliminate or suppress harmonic components and achieve the purpose of purifying the power supply.
(3) Keep the wiring of this type of equipment as far as possible from the line with severe harmonic current distortion to avoid electromagnetic interference in space.
However, these measures do not govern harmonic pollution from the source.
According to the requirements of national standards for power grid harmonics, ANAPF low-voltage active filters can be used to eliminate harmonics from the purpose of improving system power quality, ensuring equipment safety and normal operation, comprehensively improving equipment operating efficiency and power energy efficiency. It can effectively and cleanly absorb harmonics and surges in the line. To achieve optimized line power quality, reduce harmonic hazards, achieve protection of equipment operation, and save electricity.
3.1 ANAPF working principle ANAPF series active power filter device is connected to the grid in parallel mode. By detecting the harmonic and reactive components of the load in real time, PWM converter technology is used to generate a current harmonic component from the converter. The inverse component corresponding to the reactive component is injected into the power system in real time to achieve harmonic control and reactive power compensation.
The principle of ANAPF is shown in Figure 1:
4. Application examples of ANAPF low-voltage active filter in business hotels The total construction area of ​​the business hotel is 200,000 square meters. The central air-conditioning and elevators are all frequency-controlled and dragged. Several large data rooms are equipped with UPS, and EIB is installed in the whole building. Intelligent lighting system. According to the load rate of the transformer non-linear load equipment of the business hotel and the corresponding harmonic distortion rate, the ANAPF active filter is arranged next to the transformer bus of the power distribution room and the inverter of the central air conditioner. Secondly, the ANAPF active filter is arranged next to important equipment such as the central control room, weak motor room and presidential suite.
The following is a detailed description of the comparative analysis of the power quality test of the power distribution system before and after the ANAPF active filter is put into operation in the distribution transformer bus of the distribution room.
4.1 Data before and after the active filter operation (1) The current waveform distortion before the active filter input is serious. The three-phase current harmonic content is 30.5%, 35.2%, 29.7%, respectively, and the three-phase current is 147A, 168A, respectively. 148A, neutral current is 1A.
(2) The distortion of the current waveform after the active filter is input is obviously improved, and the harmonic content of the three-phase current is significantly reduced, which are 3.1%, 4.1%, and 3.7%, respectively. The three-phase currents are 144A, 168A, and 148A, respectively. The current is 1A.
4.2 Test data before and after the active filter is put into operation
5 ANAPF low voltage active filter offer and main components list
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