Lighting power supply
Street lamp individual transformers should power lighting power supply urban street lighting.
Dual power sources shall power the lighting of the principal roads in the city, transportation hubs, and squares where people are concentrated.
Each power supply should be able to withstand 100% of the load.
Under normal operating conditions, the lighting terminal voltage should be maintained at 90% to 105% of the rated voltage.
The design of road lighting supply and distribution system should meet the following requirements:
1 The power supply network is designed to meet the needs of the plan.
The load factor of the distribution transformer should not be higher than 70%.
Underground cable lines should be used for power supply. When overhead lines are used, overhead insulated distribution lines should be used.
2 The transformer shall be a three-phase distribution transformer with D, yn11 as the tie-line group, and the transformer ratio and voltage tap shall be selected correctly;
3 Should take compensating reactive power measures;
4 The three-phase load should be balanced.
1. The cross-section of the neutral line of the distribution system should not be less than that of the conductors of the phase conductors and should meet the requirements for unbalanced currents and harmonic currents.
2. Road lighting distribution circuit should set up protection devices, each lamp should be equipped with a separate protection device.
3. Light poles or other lighting devices installed on tall buildings shall be equipped with lightning protection devices and shall comply with the current national standard “Code for the design of lightning protection of buildings” GB50057.
4. The manhole covers and handhole covers for road lighting power supply lines, access doors for lighting poles, and outdoor distribution boxes for street lamps should be equipped with a locking anti-theft device that requires the use of special tools.
5. TN-S system or TT system should be used for the grounding form of road lighting distribution system.
Exposed conductive parts of metal poles and components, lamp housings, power distribution and control box screens should be protected and grounded. The current national standards require.