The need for double phasing and neutral open protection in Solar power plant design
Generally any equipment will get damaged due to 3 primary reasons.
- Lightning or surges
- Temporary over voltages.
First 2 reasons are taken care of in design and considered as per worst case scenario.
However safeguards for temporary over voltage are generally not taken, certainly not considered as per worst case scenario.
In secondary side of LT transformer , worst case scenario is 440V in single phase.
It happens more often than expected.
Reasons for 440V coming in your supply
- Neutral open condition
- Double phasing
Causes of neutral open.
- Uneven load distribution
- Loose wiring.
- Accidental breakage
- Maintenance work errors
Causes of double phasing
- Trees falling on overhead wires
- Touching of overhead wires running through trees.
Majority of projects are located outside of city limits due to roof space constraints and industry requirements. Such scenarios are very common
Not one of the available solar inverter can handle a continuous over voltage of the above nature and will get damaged resulting in down time.
There is strong need of safeguard against such issue in design stage itself so that such issues can be tackled with min losses.
To illustrate, if there is short circuit or lighting strike, the system is designed to handle it. However for continuous over voltage there is not a single solution that can be offered.
There is infact no solution incorporated for 440V in single phase. Most of integrators rely on the inverters capacity of handling voltage fluctuation, and they will definitely get damaged in such a situation.
This is where it is recommended to take cognizance of potential problem that can be taken care in design stage itself.
We specialise in this area i.e. Neutral open and double phasing protection.
You can see our website www.microsystemservices.com for details on how we can add value to solar field.