introduction
Currently, backup power for communication base stations mainly relies on small, air-cooled diesel generators , whose primary fuel is diesel. The use of diesel has many inconveniences, such as its large weight, high noise level, and difficulty in starting. The noise is primarily low-frequency and has strong penetrating power. During prolonged engine operation, the temperature and pressure are high, resulting in significant amounts of soot and carbon deposits in the cylinders. Engine oil also easily oxidizes, producing gum deposits, leading to a large workload and frequent maintenance. The exhaust gas contains large amounts of CO, soot, and nitrogen oxides, and the particles are relatively large, easily producing "black smoke."
Compared to diesel generators, natural gas generators overcome many of the disadvantages of diesel generators . For example, they offer quieter operation, cleaner combustion with fewer impurities, more even and gentler power delivery, longer component lifespan, and the absence of oil buildup from exhaust gases in equipment and generator rooms, making them a recognized green energy source. Since the fuel itself is a gas, it does not require vaporization before combustion, does not adhere to the combustion chamber or spark plugs, produces no carbon deposits, and does not contaminate lubricating oil, reducing daily maintenance and upkeep costs. Therefore, natural gas generators have broad application prospects in communication base stations.
1. Working principle of natural gas generator
The natural gas generator set system is based on the gasoline generator set. The gas is input into the engine cylinder through a dedicated gas channel, so that the engine can do work to drive the generator to generate electricity.
The natural gas power generation system is permanently installed inside the mobile communication base station. It generates electricity using natural gas and automatically supplies three-phase power to the base station equipment based on intelligent judgment of the availability or absence of mains power. The entire system forms a relatively closed self-circulating system through air inlets and outlets, which has no impact on the air and temperature inside the base station.
2. System composition of natural gas generator
The system mainly consists of a gas generator main unit, an automatic control system, a noise reduction and vibration damping system, and a gas system.
2.1 Gas-fired generator
The working principle of the gas-fired generator is the same as that of a gasoline generator. After reliability modifications and improvements, the only difference is that the fuel is changed from gasoline to natural gas, utilizing mature and stable internal combustion engine technology. The generator outputs stable and reliable AC power, and the steady-state regulation rate and fluctuation rate of voltage (frequency), line voltage deviation under unbalanced load, sinusoidal distortion rate of line voltage waveform, transient voltage (frequency) regulation rate, and settling time all meet national standards.
2.2 Automatic Control System
Equipped with an automatic control system, it can monitor the unit's operating status in real time, truly achieving unmanned operation of the machine room.
In addition to working with the combustible gas sensors inside the enclosure, the automated monitoring system can also work with indoor combustible gas sensors to transmit alarms to the automatic control box, thereby cutting off the gas pipeline, locking the unit's operation, and ensuring the overall safety of the equipment room. Simultaneously, the automated monitoring system, in conjunction with the temperature and oil level sensors inside the enclosure, closely monitors the unit's operating status. When the temperature exceeds the safety setpoint, it directly stops the unit's operation, locks it, and cuts off the gas pipeline. It can be managed by the mobile operation and maintenance management center via an RS222 interface, centrally monitoring the operating status of each base station unit, including signals and alarm information such as voltage, current, frequency, temperature, gas level, and oil level. The center can also remotely control the unit's start and stop as needed.
The automatic control system can realize the following safety protection functions: overvoltage protection, undervoltage protection, overload protection, frequency protection, gas leakage protection, chassis temperature protection, low oil level protection, and coolant temperature protection.
2.3 Silent Vibration Reduction System
The noise reduction and vibration damping system includes a noise reduction and vibration damping housing and an air intake and exhaust silencer. The noise reduction system greatly reduces the mechanical noise of the engine. Combined with the noise reduction and vibration damping housing and the large air duct silencer, it meets the requirements for high quietness.
With the enhanced configuration, the noise level can be as low as 45dB, meeting the requirements of various environments.
2.4 Gas System
The gas system mainly consists of gas storage tanks and gas control components. In recent years, the mature gas cylinder storage technology has created basic conditions for the promotion of natural gas generators. At present, the use of gas cylinders should comply with national safety standards.
2.5 Operating Model of Natural Gas Generator
The natural gas generator is installed in the communication base station and its AC output is connected to the existing AC input distribution box of the base station. In the event of a mains power outage, battery power is prioritized. Once the battery discharges to a certain level (detected by voltage detection), the natural gas generator automatically starts generating electricity. After starting, the generator can power all electrical equipment within the base station.
The natural gas generator's automatic control system has an RS222 intelligent output interface, which can be directly connected to a mature and comprehensive monitoring network. The monitoring center can read various operating data and statuses of the natural gas generator, such as voltage, current, frequency, temperature, gas level, oil level, and alarm information.
Natural gas generators are fixedly installed within the base station and can be considered for applications in the following situations:
a. Portable diesel generators cannot be brought into the area where they generate electricity.
b. For areas where portable diesel generators are particularly sensitive to noise.
c. Base stations that are far from the power generation support center.
