Lightning: Municipal office is endanger on the condition of lightning strike and we always focus on electrical safety at risk of lightning.and there are equipment of communication , computer , and electronic devices easily being influenced by lightning strikes.
When it hamper the working of equipment and officers because of equipment damaged or malfunction, it is important for hard base unit of municipal administration related to citizen benefit and country development .
Arc fault: Over-current protector prevent the arc fault short circuit related to the metal short circuit in municipal building. Faulty connection and short circuit in single phase with ground, leading to electrical spark and arc .
Continual arc happened on condition of high resistance at low current in fault point , because breaker can’t function due to fire accident. Non-stop working in building is an obligation to lighting system , elevator , air condition , water pipeline , anti-fire and office system . Long-time operating in complex environment is necessarily prevented from poor power quality .
Harmonic and three phase unbalance : Harmonic due to mass use of equipment and voltage and current in three phase unbalance give serious impact on power quality to building .
1 Harmonic current and current in three phase unbalance , both of two is more than rated level, leading to loss of transformer or other power equipment . aging lay of insulation and heat, damage equipment .
2 In three phase /four wire low voltage power supply system, over rated current as like harmonic current and zero-sequence current makes neutral current over-high, meanwhile it exists a potential between load neutral point and power neutral point .
3 Harmonic triggers action of power protector to make building power-off.
4 Harmonic affect transmission of signal and computer working.
5 Harmonic make the electric meter error .