Method for detecting a defective measurement of an extensive electrical quantity

Patent metadata

Field	Value
Publication number	US-10359455-B2
Application number	US-201615132535-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Apr 23, 2015
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

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
⁡

(

p
j

)

=

∑

i
=
1

N

⁢

a
i

⁢

m
i

⁡

(

p
j

)

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.

First claim

The invention claimed is:

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 other sensors, a measurement of the extensive electric quantity depending on a parameter p, the method comprising:
performing 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 once the measurements have been performed:
a) formalizing a relationship between the measurements, for each value of parameter p with equation:

M
⁡

(

p
j

)

=

∑

i
=
1

N

⁢

a
i

⁢

m
i

⁡

(

p
j

)

wherein j is an index of the parameter p, M(p j ) is a measurement of the sensor of the upstream supply for a value p j of the parameter, N is the number of downstream outlets, i is the downstream outlet initial index varying from 1 to N, m i (p j ) is a measurement from the sensor of the downstream outlet of index i for the value p j of the parameter and a i is a gain of this measurement;
b) generating a system of N equations and N unknowns, the unknowns being the gains a i ;
c) solving the system of equations by calculating each gain a i ;
d) controlling the gains a i and:
when all the gains are equal to 1, determining that no sensor has conducted a faulty measurement, and
when at least one of the gains a i is different from 1, determining that at least one sensor has conducted a faulty measurement; and

e) when the gain of the faulty measurement has a negative value for several measurements for different values of the parameter, determining that a fault of the sensor which has conducted the faulty measurement is due to the sensor being mounted upside down on the corresponding downstream outlet.

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

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

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

m
k
′

⁡

(

p
j

)

=

M
⁡

(

p
j

)

-

∑

i
=
1

,

i
≠
k

N

⁢

m
i

⁡

(

p
j

)

wherein m′ k (p j ) is the corrected measurement for the value p j of the parameter, k being the index comprised between 1 and N of the gain different from 1.

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

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

M
k
′

⁡

(

p
j

)

=

∑

i
=
1

N

⁢

m
i

⁡

(

p
j

)

wherein M′(p j ) is the corrected measurement for the value p j of the parameter k.

7. The method according to claim 1 , wherein, when the gain of the faulty measurement varies between two or several measurements for different values of the parameter, determining the fault as a random fault.

8. The method according to claim 1 , wherein, when the gain of the faulty measurement remains constant between two or several measurements for different values of the parameter, determining the fault as a structural default and inherent to the sensor.

9. The method according to claim 8 , wherein a corrected gain is defined from equation:

a
k
′

=

1

a
k

wherein k is an index comprised between 1 and N, a k is the gain associated with the faulty measurement and a′ k is the corrected gain.

10. The method according to claim 1 , wherein the electric network is

Assignees

• Schneider Electric Ind Sas

Inventors

• Clot Sylvain
• Deschamps Philippe
• Ligeret Christophe

Classifications

• H02J13/00

  Circuit arrangements for providing remote monitoring or remote control of equipment in a power distribution network · CPC title

• G01R35/00

  Testing or calibrating of apparatus covered by the other groups of this subclass · CPC title

• G01R31/086

  in power transmission or distribution networks, i.e. with interconnected conductors · CPC title

• G01R19/2513 Primary

  Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging · CPC title

• G01R25/005 Primary

  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 title