A. November 9 1965: I saw the news story on the New England blackout on TV.
B. 1966: I read the report from the Federal Power Commission on the blackout. It specified that relay Q29BD had tripped, but did not find a reason for the tripping, other than "a possible sudden surge that momentarily raised the power above 375 MW."
C. 1969: I bought "Scientific Study of Unidentified Flying Objects." It has a portion of the report included, as well as a report from "IEEE Spectrum".
D. 1983: My job as an engineer requires me to build a monitor to determine the minute-by-minute usage of electrical power by Indiana University Bloomington Campus. This power is measured in three components:
The power supplied by the generators to a load is measured in watts. Reactive power is phase-shifted power, and is measured in volt-amps reactive (VAR). It is the result of AC power being fed to a load that is primarily an inductor or a capacitor. An electric motor is an example of an inductor. Although this reactive power is not taken from the generators, it does cause extra current flow through the power lines, and must be taken into account in determining the load on each wire. The resultant power, measured in volt-amperes, is the square root of the sum of the squares of the real power and the reactive power.
E. May 1996: I read the part on the blackout in "Scientific Study of Unidentified Flying Objects" again. I now noticed the following relevant facts:
Since the reactive power was right at the trip point, the starting of a single large motor would have been enough to trip the relay. It tripped, then the other relays on the parallel lines tripped as the load pulled more than 375 MW through each of them. Suddenly unloaded, generators sped up until they were out of phase with each other, and then they tripped out on high MVAR values. It is amazing that neither the investigators nor the Federal Power Commission figured this out.