Henry VI, Part 1

Henry VI, Part 1 (often written as 1 Henry VI), is a history play by William Shakespeare, and possibly Thomas Nashe, believed to have been written in 1591, and set during the lifetime of King Henry VI of England. Whereas 2 Henry VI deals with the King's inability to quell the bickering of his nobles, and the inevitability of armed conflict, and 3 Henry VI deals with the horrors of that conflict, 1 Henry VI deals with the loss of England's French territories and the political machinations leading up to the Wars of the Roses, as the English political system is torn apart by personal squabbles and petty jealousy.

Although the Henry VI trilogy may not have been written in chronological order, the three plays are often grouped together with Richard III to form a tetralogy covering the entire Wars of the Roses saga, from the death of Henry V in 1422 to the rise to power of Henry VII in 1485. It was the success of this sequence of plays that firmly established Shakespeare's reputation as a playwright.

Earth potential rise

In electrical engineering, earth potential rise (EPR) also called ground potential rise (GPR) occurs when a large current flows to earth through an earth grid impedance. The potential relative to a distant point on the Earth is highest at the point where current enters the ground, and declines with distance from the source. Ground potential rise is a concern in the design of electrical substations because the high potential may be a hazard to people or equipment.

The change of voltage over distance (potential gradient) may be so high that a person could be injured due to the voltage developed between two feet, or between the ground on which the person is standing and a metal object. Any conducting object connected to the substation earth ground, such as telephone wires, rails, fences, or metallic piping, may also be energized at the ground potential in the substation. This transferred potential is a hazard to people and equipment outside the substation.

Causes

Earth Potential Rise (EPR) is caused by electrical faults that occur at electrical substations, power plants, or high-voltage transmission lines. Short-circuit current flows through the plant structure and equipment and into the grounding electrode. The resistance of the Earth is non-zero, so current injected into the earth at the grounding electrode produces a potential rise with respect to a distant reference point. The resulting potential rise can cause hazardous voltage, many hundreds of metres away from the actual fault location. Many factors determine the level of hazard, including: available fault current, soil type, soil moisture, temperature, underlying rock layers, and clearing time to interrupt a fault.