Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbatt!neoucom!wtm From: wtm@neoucom.UUCP Newsgroups: sci.electronics Subject: Re: Domestic KiloWatt Hour Meters Message-ID: <555@neoucom.UUCP> Date: Wed, 22-Apr-87 22:25:14 EST Article-I.D.: neoucom.555 Posted: Wed Apr 22 22:25:14 1987 Date-Received: Sat, 25-Apr-87 01:48:33 EST References: <923@mhuxh.UUCP> <1715@kitty.UUCP> Organization: Northeastern Ohio Universities College of Medicine Lines: 48 Keywords: meters,power,watthour Summary: Another watt hour meter question (Hey Larry..) Not having immediate access to the publications larry mentioned in his helpful article, I thought I'd ask the Net a follow-up question. It seems to me like the process of metering that Larry described:

= + is the measure of instantaneous *REAL* power consumed by the load, as opposed to *REACTIVE* power in the circuit, whcih would not actually be energy consumed in the load. Eventhough the reactive power load doesn't dissipate energy in the customer's equipment, it would cause (I**2)*R power loss in the power co.'s lines to the customer. In essence real power woud be: p(t)=v(t)i(t)cos(theta), theta being the phase angle time difference between the voltage and power waveforms. Note that if the voltage and current are 90 degress out of phase, no actual power is delivered. This could be the case if you stuck an inductor or capacitor into your friendly wall socket. (Please don't try it, though.) I've heard of corporate customers using things called synchronous capacitors and synchonous motors to apply reactive loads to the power line to bring the phase angle of the current waveform back into step with voltage. Presumably it results in lower bills. I remeber playing with a synchronous motor in a college course and being able to widely vary the phase angle by applying a control voltage to a field coil. What I was wondering if there is any convenient way for the electric co. to measure domestic customers' reactive power load, or do they just estimate the average domestic power factor and bill everyone under the same default assumption? I presume that the electric co. keeps close tabs, and maybe even measures the phase angle at corporate customers' sites by hand. Thanks in advance for any responses, --Bill Bill Mayhew Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbatt!neoucom!wtm)