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Roof PV Fire Prevention Measures
- Jun 01, 2018 -

Fire prevention measures

According to the code for thermal power generation, combined with the characteristics of electrical equipment in photovoltaic power stations, the following measures should be taken for photovoltaic power stations:

2.1 general layout

The site selection of the photovoltaic power station should be considered according to the long-term development plan of the national renewable energy, the solar resources, the access to the power grid and the environmental protection. The fireproof space between the construction (structure), the construction (construction), the yard and the storage tank outside the power station should be in accordance with the regulations of the construction regulations. The fire lanes in large and medium-sized photovoltaic power stations should be arranged in a ring. When returning to the driveway, there should be a return area or a return lane.

2.2 fire protection measures for transformers and other electrical equipment with oil.

1) because of the oil and electrical equipment in the process of use fire easily, in order to prevent the fire spread to the adjacent construction (structure), and other construction (construction) adjacent to the adjacent walls should be set up a firewall.

2) the electric equipment with a single total oil of more than 100kg in the house, the electric equipment with a single oil amount above 1000kg, should set up the oil storage or oil retaining facilities, and the oval layer should be laid in the oil storage facilities.

2.3 fire protection measures for cable

Because of the large area and wide distribution of the cable in the photovoltaic power station, it is impossible to set a fixed fire extinguishing device for the cable. In the cable trench, the fire-retardant partition and the flame retardant cable should be used as the main measure to deal with the cable fire. The cables in the channel and slot box should be selected to select the C or C class of fire retardant cables.

2.4 operation and maintenance of photovoltaic power station

1) operators and maintenance personnel should have corresponding professional skills. It is necessary to make safe preparation before maintenance, break off all switch off, ensure the discharge of capacitance and inductance completely, wear insulating shoes when necessary, with low voltage insulating gloves, and use insulation tools. After the work is finished, the possible hidden danger of the system should be eliminated.

2) because of the particularity of components, the voltage will be generated when receiving radiation. Photovoltaic arrays are connected in series to form high voltage direct current. If they are not careful to form loops, they will cause major safety accidents. Generally, before the PV array is connected to the system, the cluster should be kept in a state of open circuit. After accessing the system, the connection of the bus box switch will be carried out. During the construction process, if the photovoltaic module is sheltered by using the shielding, and the shelter is difficult, the construction personnel shall equip with safety protection supplies to ensure safety.

3) in order to prevent overheating and short circuit accidents, inflammable and explosive materials should not be accumulated around the main parts of PV plants.

Early warning rooftop PV is on fire again. This is actually a primary school roof.

2.5 fire protection facilities

The fire water supply system should be designed at the same time by 2.5.1 fire protection to the planning and design of the hydropower station. The water supply should be guaranteed by the fire water supply, and the water supply should be calculated according to the sum of the indoor and outdoor fire-fighting water. The following can not be set:

1) the PV array area (including inverter booster chamber) should not be equipped with fire water system. The photovoltaic array area is mainly composed of electrical equipment, which is always charged on the DC side during the day, and is not suitable for extinguishing with water.

2) referring to the "thermal power generation code", there is no hydrant in the outdoor power distribution area of the substation (except for the main transformer hydrant using water spray).

3) according to the regulations of "construction regulations", the buildings within the power station are not less than two levels of fire resistance, and the volume is not more than 3000m3. And when the fire danger is AML, there is no water inside and outside the room.

The volume of the single building of the ground photovoltaic power station is generally less than 3000m3. The monitoring system has complete functions, few attendants and scattered buildings. The large scale ground photovoltaic power station is usually built in the northwest desert area, the drought is short of water, the living water is mostly used by the car transportation mode, and the water use cost is difficult to set the water fire system.

2.5.2 automatic fire extinguishing facility

According to the code of thermal power, water spray fire extinguishing system, synthetic foam spray system or other fixed extinguishing equipment should be set up for the main transformer with a single capacity of 125MV A and above. Other electric equipment with oil should be used for powder extinguisher.

Oil immersed transformer oil has good insulation and thermal conductivity. The flash point of transformer oil is usually 130 C, it is a flammable liquid. When the internal faults of the transformer are flashover, the oil is heated by heat decomposition to form a fire. Water spray and other automatic fire extinguishing systems need to be set up. It is short of water, cold, windy sand and bad operating conditions. In the area, the oil discharge extinguishing device and the synthetic foam sprinkler system can be selected, and the gas extinguishing system can be used for the transformer in the indoor closed space. For medium and small substations, automatic fire extinguishing system is relatively expensive, and fire extinguishers can be selected.

2.5.3 automatic fire alarm system

The main fire hazard sources of the photovoltaic power station are cable and electrical equipment, because the power generation capacity of the photovoltaic power station is determined by the solar radiation size. The electrical equipment load and the cable carrying capacity change with the change of the solar radiation. It is zero in the morning and night and near the design value at noon, so the probability of the fire in the photovoltaic power station is more than the conventional thermal power plant. Much smaller. Referring to the "thermal power generation code", combined with the characteristics of photovoltaic power station, a fire alarm system can be installed in a large photovoltaic power station or an unattended power station. The main control room, the relay equipment room, the reactive power compensation room, the distribution unit room can choose smoke detector. The main transformer (indoor), cable layer and cable shaft can choose the line type temperature sensitive fire detector.

2.5.4 fire power supply, emergency lighting and fire extinguisher

In order to ensure the safety of the fire power supply and the normal operation of the fire control system, the fire pump, fire alarm and fire emergency lighting should be powered by class II load. The main control room and the distribution unit room of the power station should set fire emergency lighting and evacuation sign. The power station should be set according to the requirements of GB50140 2005 "construction fire extinguisher configuration design specification". Fire Extinguisher.

Photovoltaic power generation is an emerging industry in recent years, and it is an important way to solve the future energy demand. Because there is no special fire protection design code for photovoltaic power station, this paper expounds the classification, composition, fire hazard, general layout, safety measures and fire protection facilities of the power station, which is based on the regulations of construction and fire power code. For reference.