Effective Grounding Design Tool
The Effective Grounding Design Tool from Yaskawa - Solectria Solar is useful in calculating the impedance of grounding devices - namely grounding transformer banks or neutral grounding reactors, commonly employed in effective grounding for PV plants and in estimating the neutral current with the given impedance. This tool can be used for the following calculations:
- Impedance of the neutral grounding reactor or grounding transformer bank
- Voltage Imbalance Contribution to ground current at POI
- Grid contribution to a ground fault
- Inverter contribution to a ground fault
Please refer to Figure: 1, A & B for the system configurations used to calculate the aforementioned values. As shown in the figures, the simplified network is comprised of the grid, a medium voltage transformer and the inverter (a PV plant in case of multiple inverters) along with the grounding device (transformer bank or neutral grounding reactor). The calculations assume a single grounding transformer bank for multiple inverters at the point of interconnection whereas individual grounding reactors are tied to the neutral terminal of each inverter. A single line to ground fault is applied at point A as shown in the figures below.
For more information about Effective Grounding please see the following articles:
Effective Grounding: Oregon's New Frontier - Emily Hwang, Sr. Applications Engineer
The Effective Solar Grounding Conundrum - Emily Hwang, Sr. Applications Engineer
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