Method for diagnosing an operating state of an electrical switching device and electrical switching device for implementing such a method

Patent metadata

Field	Value
Publication number	US-2022020546-A1
Application number	US-202117376248-A
Country	US
Kind code	A1
Filing date	Jul 15, 2021
Priority date	Jul 20, 2020
Publication date	Jan 20, 2022
Grant date	—

Abstract

A method for diagnosing an operating state of a switching device including separable contacts, which are driven by an electromagnetic actuator including a coil connected to an electronic control device, and sensors, which are configured to measure an intensity of a coil current and a coil voltage. The method comprises:
a) receiving an order to close via the electronic control device; b) controlling the electromagnetic actuator so that it closes; c) measuring and recording the coil voltage and coil current values; d) calculating and recording values of a magnetic flux through the coil, by integrating the recorded values of the coil current, the coil voltage and resistance and inductance values of the coil; and e) evaluating and recording positions of a core of the electromagnetic actuator according to a data table, which is previously recorded in the electronic control device and which defines a bijective relation between the position of the core, the magnetic flux and the coil current.

First claim

1 . A method for diagnosing an operating state of a switching apparatus, which apparatus is configured to be coupled to an electrical conductor and comprises:
separable contacts that are associated with the electrical conductor and that are driven by an electromagnetic actuator comprising a coil connected to an electronic control device, which control device is configured to apply a coil command voltage across the terminals of the coil, and sensors that are configured to measure a magnitude of a coil current flowing through the coil and the coil voltage,
the method comprising:
a) receiving an order to close the switching apparatus, the switching apparatus initially being in an open state, the order to close being received by the electronic control device;
b) after the order to close has been received, commanding the electromagnetic actuator to close, by means of the electronic control device;
c) as the switching apparatus switches to the closed state, measuring and storing values of the coil voltage and coil current;
d) computing and storing values of a magnetic flux passing through the coil, by integration of the stored values of the coil current and coil voltage and of values of the resistance and inductance of the coil that are stored beforehand in the electronic control device; and
e) on the basis of the stored values of the magnetic flux and coil current, evaluating and storing positions of a core of the electromagnetic actuator depending on a data table characteristic of the electromagnetic actuator, the data table being stored beforehand in the electronic control device and defining a bijective relationship between the position of the core, the magnetic flux and the coil current.

2 . The method according to claim 1 , wherein computing values of the magnetic flux comprises an initial substep, referred to as the self-correction substep, followed by a computing substep, the self-correction substep comprising, provided that the coil current is lower than a current referred to as the “start” current, below which the movable core is kept in the open position by a return member of the electromagnetic actuator, evaluating and storing an initial value of the magnetic flux, which value is referred to as the “initial flux”, so that, when the coil current increases above the start current, the computation by integration of the magnetic flux in the computing phase takes into account the value of the initial flux.

3 . The method according to claim 2 , wherein, in commanding the electromagnetic actuator to close, the electronic control device commands the electromagnetic actuator to close when the coil current reaches 50% of the value of the start current, and preferably 20%, and more preferably 10% of the start current.

4 . The method according to claim 1 , further comprising computing, from the profile of the position, which profile is stored in the electronic control device, a closing time of the electromagnetic actuator, the closing time being equal to a time difference between the time at which the electronic control device commands the electromagnetic actuator to close and the time at which the electromagnetic actuator reaches its stable closed position.

5 . The method according to claim 1 further comprising computing, by derivation with respect to time of the profile of the position stored in the electronic control device, a profile of the speed of movement of the switching apparatus and a profile of the acceleration of the switching apparatus, and storing the speed and acceleration profiles in the electronic control device.

6 . The method according to claim 5 , further comprising computing, from the profile of the speed of the switching apparatus, a minimum compression speed of the core, the minimum compression speed being equal to a minimum of the speed of the core in a terminal segment of the movement of the core in the closing phase.

7 . The method according to claim 5 , further comprising detecting precise times of closure of each contact associated with each pole of the switching apparatus by means of current sensors, and combining the profile of the speed, which profile is stored in the electronic control device, and the precise times of closure of each contact, in order to evaluate a closing speed of each contact.

8 . The method according to the claim 7 , wherein a compression associated with the movable contacts of each pole is evaluated by combining the profile of the position of the core at the precise times of closure of each contact, the compression of each movable contact being equal to the difference between a final position of the core in its stable closed position and the position of the core at the precise time of closure of the contact in question.

9 . An electrical switching apparatus for implementing a diagnosing method according to claim 1 , the switching apparatus being configured to be coupled to an electrical conductor and comprising:
separable contacts, which are moved between an open position and a closed position by an electromagnetic actuator comprising a coil and a movable core that is attached to the separable contacts, the switching apparatus having a structure that limits the generation of eddy currents; a command circuit for controlling the voltage across the terminals of the coil, which voltage is referred to as the “coil voltage”, the command circuit comprising a device referred to as the “release” device, which may be selectively activated in order to make drop the electrical current flowing through the coil, which is referred to as the “coil current”, the coil voltage and the release device being activated or deactivated depending on the states of the command circuit; sensors for measuring the coil current and coil voltage; and an electronic control device, which is configured to receive orders to open and close the switching apparatus, to receive the values of the measurements of coil current and coil voltage, and to control the states of the command circuit;
wherein the switching apparatus is configured to implement a diagnosing method comprising:
a) receiving an order to close;
b) commanding the electromagnetic actuator to close;
c) measuring and storing values of the coil voltage and coil current;
d) computing and storing values of a magnetic flux passing through the coil, by integration of the stored values of the coil current and coil voltage and of values, which are stored beforehand in the electronic control device, of the resistance and inductance of the coil; and
e) on the basis of the stored values of the magnetic flux and coil current, evaluating and storing positions of the core depending on a data table characteristic of the electromagnetic actuator, the data table defining a bijective relationship between the position of the core, the magnetic flux and the coil current.

10 . The electrical switching apparatus according to claim 9 , wherein the switching apparatus comprises current sensors, which are configured to measure a magnitude of the electrical current flowing through each phase of the electrical conductor, the switching apparatus being configured to implement a diagnosing method comprising detecting a precise time of closure of the movable contacts associated with each phase, and combining with the precise times of closure of each of the movable contacts the profile of the position of the core or the profile of the speed of the core, in order to evaluate a compression or a closing speed of each of the movable contacts.

Assignees

• Schneider Electric Ind Sas

Inventors

• Delbaere Stéphane
• Orban Rémy

Classifications

• H01H1/0015

  Means for testing or for inspecting contacts, e.g. wear indicator (measuring circuits G01R31/3274) · CPC title

• G01R31/3274

  Details related to measuring, e.g. sensing, displaying or computing; Measuring of variables related to the contact pieces, e.g. wear, position or resistance (measuring contact resistance G01R27/205) · CPC title

• G01R31/327 Primary

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

• H01H50/54

  Contact arrangements · CPC title

• H01H50/02

  Bases; Casings; Covers (frames for mounting two or more relays or for mounting a relay and another electric component H02B1/01, H04Q1/08, H05K) · CPC title