Trinity Public Utilities District’s power lines snake through the lower reaches of the Cascade Range, a rugged, remote and densely forested terrain in Northern California that has some of the highest wildfire risk in the country. But for several years, the company has been without insurance to protect it from such a threat.Trinity’s equipment was blamed for causing a 2017 wildfire that destroyed 72 homes and three years later its insurer, a California public agency called the Special District Risk Management Authority, told the utility that it would no longer cover it for fires started by its electrical lines. Trinity could find no other takers.