Siemens Power Transmission & Distribution, Inc.

Landis & Gyr Metering, Inc.

Robert E Slaven

Christopher L Anderson

John T Voisine

Randal K Bond

Ronald C Tate

Gordon G Burns

Randall K Bond

Disclosed is a method and arrangement for use in an electrical utility meter, the electrical utility meter operable to be connected to a plurality of electrical service types. The arrangement is operable to identify a present service type, the present service type being one of the plurality of electrical service types to which the electrical utility meter is connected. The arrangement comprises: conversion circuit for obtaining measured voltage magnitude and phase angle data for a plurality of phases in a polyphase electrical system; a memory; and a processor connected to said memory and said conversion circuit. The processor is operable to execute programming steps stored in the memory to receive the measured voltage magnitude and phase angle data from the conversion circuit and identify the present electrical service type based on the measured voltage magnitude and phase angle data.

Automatic service type recognition in electrical utility meter

The present invention includes an electrical utility meter operable to measure power consumption. The method detects and compensates for one or more wiring errors that affects the power consumption measurement of the electrical utility meter. The method includes the steps of: obtaining measured phase angle data for a plurality of phases in a polyphase electrical system; periodically performing one or more diagnostic tests using the measured phase angle data to determine whether a wiring error is present, automatically adjusting the operation of the electrical utility meter to effect a compensation for the wiring error, said compensation increasing an accuracy of power consumption measurement of the electrical utility meter. The meter is operable to detect and compensate for wiring errors including polarity errors and cross phasing errors. According to another method of the present invention, the meter is operable to determine automatically the service type to which it is connected.

Robust electrical utility meter

Service type recognition in electrical utility meter

A current sensing device includes a secondary coil positioned within the curved portion of a U-shaped primary conductor or coil. The secondary coil is surrounded by a non-ferromagnetic metallic shield to prevent capacitive coupling between the windings of the secondary coil and other nearby metallic objects. A nonconductive material is integrally formed about the U-shaped conductor and provides a cavity for receiving the secondary coil an shield in a predetermined position with respect to the U-shaped conductor. A flux guide of ferromagnetic metal, formed in an elliptical-cylindrical shape, surrounds the U-shaped conductor and the secondary coil to provide a flux steering effect to steer flux around the secondary or pick-up coil. The current sensing device is useful in measuring current in electrical utility power monitoring or watthour meter applications.

Shielded current sensing device for a watthour meter

A current measurement circuit for an electrical energy meter of the type having an inductive current pickup which generates a signal proportional to the derivative of current with respect to time in an electrical power line. An underdamped integrator is provided which compensates for nonideal phase characteristics of the inductive current pickup including a phase deviation from 90.degree. at the nominal line frequency. The integrator has a transfer function with a magnitude peak at a frequency below the line frequency and with a phase shift deviating from 90.degree. at the line frequency.

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Lafayette, IN, United States of America

Robert E Slaven