There’s a bill before the New Hampshire legislature “requiring utilities and electric grid operators to assess and report the vulnerability of high-voltage transformers to geomagnetic and electromagnetic disturbances, and to recommend mitigation measures to protect the state electric infrastructure.“
A lot of legislation about technical matters is vague and non-technical, because most lawmakers aren’t engineers, but not this one!
It starts with “High voltage transformers are especially vulnerable to geomagnetically induced currents—GICs—whether induced by GMDs or HEMP E3 component, entering the grid through ground-connected neutral wires” and goes on to say that some time this year utilities must “utilize the waveform in Figure A.5 of IEC 61000-2-9, Edition 2.0 (2025-05), modeling a peak magnetic field strength of 20,000 nT and corresponding electric field of 85 V/km” and “Identify susceptibility to half-cycle saturation, GIC-induced harmonics, reactive power consumption, hot spot generation, and insulation degradation” – but that they can’t “rely solely on operational procedures such as load shedding or reactive power supply to mitigate GIC risk. Such procedures shall not be considered sufficient protection under this chapter. “
Whew!
.
Return to the Concord Monitor