Phase control device

Patent metadata

Field	Value
Publication number	US-10018664-B2
Application number	US-201314905128-A
Country	US
Kind code	B2
Filing date	Aug 6, 2013
Priority date	Aug 6, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A phase control device includes a connection error detection unit. The connection error detection unit includes a phase sequence detection unit that detects a phase sequence of voltage signals, a phase sequence detection unit that detects a phase sequence of current signals, a collation unit that collates the phase sequence of the voltage signals and the phase sequence of the current signals and determines that a connection error is present when the phase sequences are different, phase difference detection units that detect a phase difference between the voltage signal and the current signal, and a phase difference determination unit that determines, when the phase differences output from the phase difference detection units fall without a determination range, that a connection error is present.

First claim

The invention claimed is:

1. A phase control device capable of opening and closing a circuit breaker connected to a main circuit, to which a phase regulation equipment capable of regulating reactive power is connected, at a target phase, the phase control device comprising:
first to third voltage measurement terminals to which three-phase voltage measurement wirings for measuring three-phase voltages of the circuit breaker are connected;
first to third current measurement terminals to which three-phase current measurement wirings for measuring three-phase main circuit currents of the main circuit are connected;
a voltage measurement unit that outputs voltage signals measured via the first to third voltage measurement terminals;
a main circuit current measurement unit that outputs current signals measured via the first to third current measurement terminals;
a connection error detection unit capable of detecting a connection error of the three-phase voltage measurement wirings and the three-phase current measurement wirings by using the voltage signals output from the voltage measurement unit and the current signals output from the main circuit current measurement unit; and
a phase regulation equipment information memory unit that stores phase regulation equipment information that is information for specifying a type of the phase regulation equipment, wherein
the connection error detection unit includes:
a phase sequence detection unit that detects a phase sequence of the voltage signals detected by the voltage measurement unit via the first to third voltage measurement terminals and a phase sequence of the current signals detected by the main circuit current measurement unit via the first to third current measurement terminals;
a collation unit that collates the phase sequence of the voltage signals and the phase sequence of the current signals output from the phase sequence detection unit and determines that a connection error is present when the phase sequences are different;
a phase difference detection unit that detects a first phase difference, which is a phase difference between the voltage signal detected via the first voltage measurement terminal and the current signal detected via the first current measurement terminal, a second phase difference, which is a phase difference between the voltage signal detected via the second voltage measurement terminal and the current signal detected via the second current measurement terminal, and a third phase difference, which is a phase difference between the voltage signal detected via the third voltage measurement terminal and the current signal detected via the third current measurement terminal; and
a phase difference determination unit that, when a collation result by the collation unit indicates that the phase sequence of the voltage signals is identical to the phase sequence of the current signals,
refers to the phase regulation equipment information in order to specify the type of the phase regulation equipment,
determines whether the first to third phase differences output from the phase difference detection unit fall within a determination range that is provided in advance and is provided in advance for the type of the phase regulation equipment in order to detect a connection error, and
when any one of the first to third phase differences does not fall within the determination range, determines that a connection error is present.

2. The phase control device according to claim 1 , further comprising:
an alarm unit, wherein
each of the collation unit and the phase difference determination unit transmits a control signal to the alarm unit so as to cause the alarm unit to output an alarm signal when each of the collation unit and the phase difference determination unit determine that a connection error is present.

3. The phase control device according to claim 1 , wherein
the connection error detection unit includes:
a first A/D converter that A/D-converts the voltage signals output from the voltage measurement unit;
a second A/D converter that A/D-converts the current signals output from the main circuit current measurement unit;
a first memory that stores the A/D-converted voltage value of the voltage signal detected via the first voltage measurement terminal;
a second memory that stores the A/D-converted voltage value of the voltage signal detected via the second voltage measurement terminal;

a third memory that stores the A/D-converted voltage value of the voltage signal detected via the third voltage measurement terminal;
a fourth memory that stores the A/D-converted current value of the current signal detected via the first current measurement terminal;
a fifth memory that stores the A/D-converted current value of the current signal detected via the second current measurement terminal; and
a sixth memory that stores the A/D-converted current value of the current signal detected via the third current measurement terminal,
the phase sequence detection unit
detects the phase sequence of the voltage signals on the basis of time-sequential voltage values read from the first to third memories, and
detects the phase sequence of the current signals on the basis of time-sequential current values read from the fourth to sixth memories, and
the phase difference detection unit detects the first to third phase differences on the basis of the time-sequential voltage values read from the first to third memories and the time-sequential current values read from the fourth to sixth memories.

4. The phase control device according to claim 3 , wherein
the phase sequence detection unit
calculates zero-cross points, which are zero points at which the time-sequential voltage values, each read from the first to third memories, change from negative to positive,
compares the zero-cross points from voltage signals each measured via the first to third voltage measurement terminals, and
detects the phase sequence of the voltage signals on the basis of the comparison;
the phase sequence detection unit
calculates zero-cross points, which are zero-points at which the time-sequential current values, each read from the fourth to sixth memories, change from negative to positive,
compares the zero-cross points from the current signals each measured via the first to third current measurement terminals,
detects the phase sequence of the current signals on the basis of the comparison; and
the phase difference detection unit
calculates, from the time-sequential voltage values, zero-cross points, which are zero-points at which the time-sequential voltage values read from the first to sixth memories change from negative to positive,
detects the first phase difference by calculating a difference between the zero-cross point of the voltage signal measured via the first voltage measurement terminal and the zero-cross point of the current signal measured via the first current measurement terminal,
detects the second phase difference by calculating a difference between the zero-cross point of the voltage signal measured via the second voltage measurement terminal and the zero-cross point of the current signal measured via the second current measurement terminal, and
detects the third phase difference by calculating a difference between the zero-cross point of the voltage signal measured via the third voltage measurement terminal and the zero-cross point of the current signal measured via the third current measurement terminal.

5. The phase control device according to claim 1 , wherein
the connection error detection unit includes:
a first comparator that binarizes and outputs the voltage signal detected via the first voltage measurement terminal;
a second comparator that binarizes and outputs the voltage signal detected via the second voltage mea

Assignees

• Mitsubishi Electric Corp

Inventors

• Yamamoto Aya
• Mori Tomohito
• Matsumoto Daigo

Classifications

• G01R31/67 Primary

  Testing the correctness of wire connections in electric apparatus or circuits · CPC title

• G01R31/327 Primary

  Testing of circuit interrupters, switches or circuit-breakers · CPC title

• H01H33/59

  Circuit arrangements not adapted to a particular application of the switch and not otherwise provided for, e.g. for ensuring operation of the switch at a predetermined point in the AC cycle · CPC title

• G01R23/005

  Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller (comparing phase or frequency of 2 mutually independent oscillations in demodulators) · CPC title

• G01R25/00

  Arrangements for measuring phase angle between a voltage and a current or between voltages or currents · CPC title