Automated three phase power monitoring system

• US 8,786,991 B1
• Filed: 09/26/2012
• Issued: 07/22/2014
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Torres, Michael A.
• Primary Examiner(s): BAUER, SCOTT ALLEN
• Application Number:
  US13/627,514
• Time in Patent Office: 664 Days
• Field of Search: 361/79
• US Class Current: 361/79
• CPC Class Codes: H02H 3/021 concerning the disconnection itself, e.g. at a particular instant, particularly at zero value of current, disconnection in a predetermined order disconnection at zero value in general H03K17/18
• CPC Class Codes: H02H 3/083 for three-phase systems

Abstract

Embodiments of the invention relate to automated three phase power monitoring systems. Embodiments of the invention include a zero crossing activated switch having an overload condition signal input that is electrically connected to a signal output terminal. The zero crossing activated switch prohibits conduction of the overload condition signal to a neutral ground RMS reactive breaker control mechanism until the zero crossing activated switch determines that at least one of three alternating currents crosses zero relative to a neutral signal.

Claims

1. A power monitoring system, comprising:

a first circuit conductor to carry a first alternating current;

a second circuit conductor to carry a second alternating current;

a third circuit conductor to carry a third alternating current;

a ground wire to carry a ground signal;

a neutral wire to carry a neutral signal;

a three pole magnetic circuit breaker having a common trip breaker, a first current sensor and circuit breaker control system associated with said first circuit conductor, a second current sensor and circuit breaker control system associated with said second circuit conductor, a third current sensor and circuit breaker control system associated with said third circuit conductor, a neutral-ground RMS reactive breaker control, a first pole associated with said first circuit conductor, a second pole associated with said second circuit conductor, and a third pole associated with said third circuit conductor;

wherein said common trip breaker is adapted to interrupt electrical flow across each of said first pole said second pole and said third pole when current flowing through any of said first input terminal said second input terminal and said third input terminal is greater than a predetermined current value;

wherein said common trip breaker is adapted to interrupt electrical flow across each of said first pole said second pole and said third pole when an overload condition signal is applied to said neutral-ground RMS reactive breaker control mechanism;

an ac to dc converter having a converter output terminal and being electrically connected to said first conductor, said second conductor, and said third conductor, wherein said ac to dc converter is adapted to convert at least a portion of said first alternating current, said second alternating current, and/or said third alternating current, to direct current power and output said direct current power through said converter output terminal;

a voltage detection module having a plurality of electrical components, a signal output terminal electrically connected to said breaker control mechanism input, a neutral wire input electrically connected to said neutral wire, a ground wire input electrically connected to said ground wire, a power wire input electrically connected to said converter output terminal;

wherein said plurality of electrical components includes a plurality of active electronic components;

wherein said plurality of electrical components is adapted to monitor an RMS voltage between said neutral wire and said ground wire using said plurality of active electronic components powered by at least a portion of said direct current power delivered from said converter output terminal to said power wire input;

wherein said plurality of electronic components is adapted to assert said overload condition signal to said neutral-ground RMS reactive breaker control mechanism when said plurality of electrical components have determined that said RMS voltage between said neutral wire and said ground wire is greater than a pre-determined voltage value for a pre-determined duration; and

a zero-crossing activated switch having an overload condition signal input electrically connected to said signal output terminal, said zero crossing activated switch being adapted to prohibit conduction of said overload condition signal to said neutral-ground RMS reactive breaker control mechanism until said zero crossing activated switch determines that at least one of said first alternating current, said second alternating current, and said third alternating current crosses zero relative to said neutral signal.

2. The system of claim 1, wherein said zero-crossing activated switch is a semiconductor having a base lead, a collector lead and an emitter lead;

wherein said emitter lead is electrically associated with one of said first circuit conductor, said second circuit conductor, and said third circuit conductor to monitor one of an applied of said first alternating current, said second alternating current, and said third alternating current;

wherein said collector lead is electrically associated with neutral; and

wherein said zero-crossing activated switch prohibits conduction of said overload conduction signal to said neutral-ground RMS reactive breaker control mechanism by remaining electrically open until said zero-crossing activated switch determines that said applied of said first alternating current, said second alternating current, and said third alternating current is at zero cross relative to said neutral.

3. A method, comprising:

applying a first alternating current to a first circuit conductor;

applying a second alternating current to a second circuit conductor;

applying a third alternating current to a third circuit conductor;

monitoring said first alternating current, said second alternating current, and said third alternating current using at least one pilot device in a three pole circuit breaker;

converting a portion of said first alternating current, said second alternating current, and/or said third alternating current to direct current power;

carrying a neutral wire voltage on a neutral wire, wherein said neutral wire voltage corresponds to an imbalance between power carried on said first circuit conductor, said second circuit conductor and said third circuit conductor;

monitoring an RMS difference between said neutral wire and a ground wire using a plurality of passive and active components in a voltage detection module, wherein said active components are powered by said direct current power;

interrupting electrical flow across each of said first pole, said second pole and said third pole by tripping a common trip breaker in response to said active and passive components having determined that said RMS difference between said neutral wire voltage and said ground wire is greater than a pre-determined threshold voltage value for a pre-determined duration;

wherein said monitoring said RMS difference between said neutral wire and said ground wire comprises;

generating a filtered voltage signal by removing all frequency components above 10 KHz between said neutral wire and said ground wire;

converting said filtered voltage signal to said RMS difference;

comparing said RMS difference to said pre-determined voltage value; and

measuring a duration for which said RMS difference continuously exceeds said pre-determined voltage value.

4. The method of claim 3, wherein said tripping a common trip breaker step comprises:

asserting an overload condition signal from said voltage detection module to a zero-crossing activated switch; and

conducting said overload conditional signal from said zero-crossing activated switch to a neutral-ground RMS reactive breaker control mechanism adapted to trip said common trip breaker in response to at least one of said first alternating current, said second alternating current, and said third alternating current crossing zero relative to neutral.

5. The method of claim 3, asserting an overload signal from said voltage detection module to said common circuit breaker.

6. A method, comprising:

applying a first alternating current to a first circuit conductor;

applying a second alternating current to a second circuit conductor;

applying a third alternating current to a third circuit conductor;

monitoring said first alternating current, said second alternating current, and said third alternating current using at least one pilot device in a three pole circuit breaker;

converting a portion of said first alternating current, said second alternating current, and/or said third alternating current to direct current power;

carrying a neutral wire voltage on a neutral wire, wherein said neutral wire voltage corresponds to an imbalance between power carried on said first circuit conductor, said second circuit conductor and said third circuit conductor;

monitoring an RMS difference between said neutral wire and a ground wire using a plurality of passive and active components in a voltage detection module, wherein said active components are powered by said direct current power;

interrupting electrical flow across each of said first pole, said second pole and said third pole by tripping a common trip breaker in response to said active and passive components having determined that said RMS difference between said neutral wire voltage and said ground wire is greater than a pre-determined threshold voltage value for a pre-determined duration;

wherein said tripping a common trip breaker step comprises;

asserting an overload condition signal from said voltage detection module to a zero-crossing activated switch; and

conducting said overload conditional signal from said zero-crossing activated switch to a neutral-ground RMS reactive breaker control mechanism adapted to trip said common trip breaker in response to at least one of said first alternating current, said second alternating current, and said third alternating current crossing zero relative to neutral.

7. The method according to claim 6, asserting an overload circuit signal from said voltage detection module to said common circuit breaker.

8. The method of claim 6, wherein said monitoring said RMS difference between said neutral wire and said ground wire comprises:

generating a filtered voltage signal by removing all frequency components above 10 KHz between said neutral wire and said ground wire;

converting said filtered voltage signal to said RMS difference;

comparing said RMS difference to said pre-determined voltage value; and

measuring a duration for which said RMS difference continuously exceeds said pre-determined voltage value.