Nitrogen Injection System

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Nitrogen Injection System

FMD Explosion Prevention & Fire Protection System became more advanced fire pretection and explosion prevention system for the Oil immersed transformer protection after "Water Spray System" and "CO2 Spray System", which obtained Shenzhen High-Tech Project Ccertificate issued by the  Shenzhen Bureau of Science and Technology. FMD Systems were also examined by "National Fixed Fire Extinguishing Systems and Components Quality Supervision and Inspection Center" and passed the test as qualified.

Transformer are among the most expensive equipment located in powe plants and substations. They generally contain a large quantity of combustible substance, which can spray fire to nearby installations and caused a power failure and huge economic losses. Special attention should therefore be given to their protection. The traditional  protection of transformer is usually focus on the electric parameters of the transformer, while the sudden pressure increase within the tank result from insulation breakdown do not give much attentions.

Principle of Explosion Prevention:
If the transformer is not working properly, an enormous amount of flammable gases is created in the oil tank. As a result, the gas relay closes and the electric breaker switches off. At this moment, the internal pressure of the tank increases due to the thermal inertia. Once the pressure exceeds the setting value of the pressure relief valve (PRV) and the setting value of rupture disk, FMD system is operated immediately. Consequently, the oil drain valve opens to draw off oil in order to relieve the pressure inside the tank and prevent any explosion and fire.

Principle of Extinct Fire:
When the transformer is on fire, the fire detector is activated, the gas relay closes, and the electric breaker switches off. As a result, FMD system is operated and  the oil drain valve opens to draw off oil. Then nitrogen gas is continuously injected, the large amount nitrogen gas sufficiently cools down the transformer, extinguishes fire, and prevents any re-combustion.

Explosion Prevention and Fire Extinguishing
The system can extinguishing the fire immediately thro injected the N2 gas into the Transformer Tank.
The Nitrogen can be injected continuously for 30 mins to stir and cool down the transformer oil, which also isolated the air from the tank.

Characteristics of FMD:
State-of-art concept: rapidly drain oil to prevent explosion and inject nitrogen to prevent and extinct fire.
Excellent performance: utilizing fast valves to drain oil in 0.1s with the technic from the national defence.
Fast response: once a fault signal is detected from the transformer. The oil can be drained within 0.2 second after detection in order to release pressure and to avoid explosion. The nitrogen gas is injected after 1 to 20 second in order to mix and cool down the oil, to reduce the concentration of flammable gases, to isolate oxygen gas, and to extinct fire.
High reliability: utilizing the principle of logic signal to prevent any improper or unnecessary activity to the system and to provide a more flexible system.
High efficiency: able to inject nitrogen gas continuously for more than 30 min to completely cool down the transformer oil as well as prevent and extinguish fire.
Reduce pollution: no environmental pollution due to the characteristic of nitrogen gas in FMD. Extinct fire without water is an advantage to the lack of water area.
Feasibility: easy to install and maintain for both new or existing transformers with reasonable investment in a minor price compare to other traditional transformer fire extinction systems, such as water spraying systems and CO2 spraying systems.
Patent right: National Patent Number 02225196.0

Scope of applications: Generator power unceasingly increase with the development of technology, there are many transformer explosion happened due to ineffective of current breaker between the Generator and Powe Transformer. FMD System is suitable for new or remodeled power transformer which located in the high power plant, substations, indoor substaions, underground substations, city substations, and cold and lack of water area. FMD system is mainly consisted of Fire Cabinet, Control Cabinet (including Control Box, the UPS power supply can be offered according to the customers’ requirements), Shutter, Fire Detector, Fire resistant cables, Control Cables, and Connections Pipes.