METHOD FOR DETECTING A DEFECTIVE MEASUREMENT OF AN EXTENSIVE ELECTRICAL QUANTITY

• US 20160313383A1
• Filed: 04/19/2016
• Published: 10/27/2016
• Est. Priority Date: 04/23/2015
• Status: Active Grant

• Current Assignee: Schneider Electric Industries SAS (Schneider Electric SE)
• Original Assignee: Schneider Electric Industries SAS (Schneider Electric SE)
• Inventors: CLOT, Sylvain, LIGERET, Christophe, DESCHAMPS, Philippe
• Granted Patent: US 10,359,455 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01D 2204/22 Arrangements for detecting or reporting faults, outages or leaks
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 25/005 Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller, or for passing one of the input signals as output signal
• CPC Class Codes: G01R 31/086 in power transmission or distribution networks, i.e. with interconnected conductors
• CPC Class Codes: G01R 31/40 Testing power supplies testing photovoltaic devices H02S50/10
• CPC Class Codes: G01R 35/00 Testing or calibrating of apparatus covered by the other groups of this subclass
• CPC Class Codes: H02J 13/00 Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
• CPC Class Codes: Y04S 10/52 Outage or fault management, e.g. fault detection or location
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

In an electric network (1) which comprises an upstream supply (2) and at least two downstream outlets, the supply and the outlets are each provided with a sensor (6) for measuring an extensive electric quantity and each sensor conducts, in a synchronous way with the other sensors, a measurement of this quantity depending on a parameter. This method comprises at least N measurements of the value on the upstream supply and on each downstream outlet conducted for different values of the parameter p. Then, the relationship between the measurements is formalized, for each value of the parameter p with the equation:

$M\left(p_j\right)=\sum _{i=1}^Na_im_i\left(p_j\right)$

A system with N equations and N unknowns is generated, the unknowns being the gains a_i, the system of equations is solved, by calculating each gain, and the gains are controlled. If all the gains are equal to 1, it is considered that no sensor has conducted a faulty measurement. If at least one of the gains is different from 1, it is considered that at least one sensor has conducted a faulty measurement.

Claims

1. A method for detecting a faulty measurement of at least one extensive electric quantity of an electric network comprising an upstream supply and at least two downstream outlets, the supply and the outlets being each provided with a sensor for measuring the extensive electric quantity, each sensor conducting, in a synchronous way with the other sensors, a measurement of the extensive electric quantity depending on a parameter p, wherein the method comprises at least N measurements of the value on the upstream supply and on each downstream outlet conducted for different values of the parameter p, and wherein once the measurements have been made:

a) the relationship between the measurements is formalized, for each value of the parameter p with the equation;

2. The method according to claim 1, wherein a sensor which has conducted a faulty measurement for the parameter is identified via the gain which is associated with it.

3. The method according to claim 2, wherein when a gain is different from 1, the sensor with which it is associated is considered as having conducted a faulty measurement.

4. The method according to claim 3, wherein a corrected value of the faulty measurement is defined from the equation:

5. The method according to claim 2, wherein, when all the gains have an identical value and different from 1, the sensor of the upstream supply is considered as having conducted a faulty measurement.

6. The method according to claim 5, wherein a corrected value of the faulty measurement is defined from the following equation:

7. The method according to claim 1, wherein the type of fault of the sensor which has conducted the faulty measurement is diagnosed.

8. The method according to claim 7, wherein, when the gain of the faulty measurement varies between two or several measurements for different values of the parameter, the fault is identified as a random fault.

9. The method according to claim 7, wherein, when the gain of the faulty measurement remains constant between two or several measurements for different values of the parameter, the fault is identified as a structural default and inherent to the sensor.

10. The method according to claim 9, wherein, when the gain of the faulty measurement has a negative value for several measurements for different values of the parameter, the fault is identified as being due to the fact that the sensor is mounted upside down on the corresponding downstream outlet.

11. The method according to claim 9, wherein a corrected gain is defined from the equation:

12. The method according to claim 1, wherein the electric network is a multiphase electric network including a number H of electric phases, H being an integer greater than or equal to two, this electric network including a group of H upstream supplies and, for each electric phase, at least two downstream outlets, the upstream supplies and each outlet including a sensor for measuring the extensive electric quantity depending on the parameter p and wherein, the step a) is applied for each electric phase, in order to formalize the relationship between the measurements of the sensors of this electric phase, in order to detect a fault of a sensor associated with this electric phase.

13. The method according to claim 12, wherein the sensors which have conducted a faulty measurement are identified by controlling the gains of the measurements from the sensors associated with at least two distinct phases of the electric network.

14. The method according to claim 13, wherein, when the gain of a first faulty measurement of a sensor on an electric phase of the electric network and the gain of a second faulty measurement of another sensor on another electric phase of the electric network are equal, respectively to the ratio of the values of the second and first faulty measurements and to the ratio of the values of the first and second faulty measurements, then the fault is identified as being due to the swapping of both of these two sensors between these different phases of the electric network.

15. The method according to claim 10, wherein it further includes, the determination of a phase angle for each value measured by the sensors of a same electric phase of the electric network, the sensor at the origin of the faulty measurement being identified as the one which has a value of a phase angle corresponding to the difference between the phase angle associated with the measurement of the sensor of the upstream supply on the one hand and the sum of the phase angles associated with the measurements of the sensors of the downstream outlets for this electric phase on the other hand.