1. Background introduction
In order to improve the medical and health service functions of a certain district in Beijing as an urban sub-center, and to enhance the medical and health service capabilities of the district as an urban sub-center, the Health and Family Planning Commission of the District, with the strong support of the district government and the municipal government, built a hospital in the district and delivered it to the People's Hospital of Peking University for free.
Rendering of the hospital area
The establishment and use of the hospital will not only meet the medical needs of patients in the southeast area of Beijing, but will also become the core of regional medical treatment in this district of Beijing, Xianghe County, Dachang County, Sanhe City and Wuqing District of Tianjin city. The core is to contribute to the coordinated development of Beijing, Tianjin and Hebei Province and the strategic deployment of alleviating non-capital non capital functions.
2. Existing problems
A large number of advanced medical equipment, such as nuclear magnetic resonance, CT machine, X-ray machine, hemodialysis machine, as well as various energy-saving lighting equipment, frequency conversion air-conditioning, elevator equipment and so on, have been put into use. It brings harmonic and three-phase unbalance problems to medical institutions, which is easy to cause medical accidents.
Main typical load
Ventilation equipment: in order to save energy, the hospital adopts frequency conversion fan and air conditioner. The frequency converter is a very typical harmonic source, its current distortion rate is more than 33%, which will produce a large number of (6N ± 1) harmonics such as 5th, 7th, 11th, 13th;
Lighting equipment: because the hospital uses a large number of energy-saving fluorescent lamps, a large amount of harmonic current will be generated. When the fluorescent lamps are connected to a three-phase four-wire load, a large third harmonic current will flow through the central line;
Electronic medical precision equipment: the large-scale electronic medical equipment in large hospitals is generally powered by switching power supply, which will produce 3,5,7,9 and (2n ± 1) harmonics;
Computer and UPS power supply: at present, the hospital is managed by computer networks, and there are a lot of computers. In addition, the server and other data storage systems must be equipped with UPS and other standby power supply. The switching power supply and UPS of the personal computer are all harmonic sources, which will generate a large number of (2n ± 1) harmonics such as 3,5,7,9.
The harmonic characteristics of hospital power distribution system are as follows:
Main hazards: due to the existence of harmonics, operators often encounter the failures of these advanced medical instruments and equipment in their work, ranging from data errors, blurred images, loss of information, interference to work, and sudden hardware damage, software Under the impact, the equipment cannot continue to work normally. Especially the instruments and equipment that detect the bioelectrical signal of human body, such as electrocardiogram, electroencephalogram, ECG monitor, ultrasonic diagnostic instrument, and other instruments that directly contact the human body. Because the signals are very weak, if the signal is interfered, a kind of distortion (harmonic) similar to some pathological changes will be superimposed on the detection results such as waveform, graph and image, which will cause misdiagnosis and also cause micro electric shock.
3. Reactive power compensation design
3.1 Reactive power compensation design
According to the load type and transformer capacity of Peking University People's Hospital, the design capacity configuration of reactive power compensation between incoming cabinet and load is as follows:
3.2 Product introduction
SFR-M series intelligent dynamic harmonic suppression reactive power compensation module of Jiangsu Sfere Electric is a kind of integrated reactive power compensation product, which aims at the harmonic and power factor problems in the 0.4KV low-voltage distribution network where the harmonic pollution is serious, so as to achieve power factor improvement, effective harmonic suppression, reduce line loss and improve power quality.
The intelligent dynamic harmonic suppression reactive power compensation module includes: DSP digital processing circuit, highly integrated detection, control, protection, display unit, zero-crossing switching module, discharge and air cooling unit, filter reactor, low-voltage filter power capacitor and function module operation status indication circuit. This series of modules is a new generation of dynamic filtering and compensation equipment for 0.4kV low-voltage distribution network. It is suitable for applications where the load changes frequently and the voltage qualification rate is extremely high. The total time of judging switching and switching action is less than 20ms. It is a typical dynamic tracking compensation integrated module.
3.3 Technical parameters
3.4 Module system diagram
4. Project summary
SFR-M series intelligent dynamic harmonic suppression reactive power compensation module of Jiangsu Sfere Electric can realize the function of high efficiency harmonic filtering. Meanwhile, the compensation module is equipped with a series reactor, which limits the closing inrush of the compensation branch on the one hand, and on the other hand, it can suppress the harmonic.
Through the application of centralized reactive power compensation in the hospital area of Peking University People's Hospital, the power factor of each transformer's incoming cabinet has been increased to 0.98. The power consumption of the hospital meets the reward requirements of the power supply department and brings actual economic benefits to the enterprise. At the same time, the reactive power compensation device can not only improve the power factor, save the active power, reduce the line loss and transformer loss, reduce the operation cost, but also can comprehensively control the harmonic and reactive power in the hospital power distribution system, optimize the power quality, and finally achieve the purpose of energy saving.
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