US 11,187,727 B2Granted

Capacitance-coupled voltage transformer monitoring

AssigneeSchweitzer Engineering Laboratories, Inc.

InventorsTravis C Mallett, Robert Lopez, Jr.

Life of this patent

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Abstract

The present disclosure pertains to systems and methods for monitoring a capacitance-coupled voltage transformer (CCVT) in electrical communication with the electric power delivery system, the CCVT comprising a stack of capacitors and an electrical contact to a first ground connection. A first current transformer is disposed between the stack of capacitors and the first ground connection. The current transformer provides an electrical signal corresponding to a current associated with the CCVT. A second current transformer is disposed between a primary winding of a step-down transformer associated with the CCVT and a second ground connection. An intelligent electronic device (IED) in electrical communication with the current measurement devices monitors a ratio of magnitudes from the current transformers at a single frequency. The ratio is compared against an acceptable range. When the ratio exceeds the acceptable range, an alarm is generated.

Claims20

Dependent claims

A system to monitor the health of a capacitance-coupled voltage transformer (CCVT) of an electric power delivery system, comprising:

a CCVT in electrical communication with the electric power delivery system, the CCVT comprising a stack of capacitors and an electrical contact to a first ground connection;
a first current measurement device disposed between the stack of capacitors and the first ground connection, the first current measurement device to provide a first electrical signal corresponding to a first current flowing through the CCVT;
a step-down transformer comprising a primary winding electrically connected to the stack of capacitors;
a second current measurement device electrically coupled to the step-down transformer, the second current measurement device to provide a second electrical signal corresponding to a second current flowing through the step-down transformer;
an intelligent electronic device (IED) in electrical communication with the first and second current measurement devices, to:
receive the first electrical signal from the first current measurement device;
receive the second electrical signal from the second current measurement device;
calculate a health factor for a common frequency from the first and second electrical signals;
compare the health factor against a health range;
and
when the health factor exceeds the health range, signal an alarm.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/396,939Filed 29 Apr 2019
Published: US 2020/0341035 A129 Oct 2020
Granted: 30 Nov 2021
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G01R 15/06
Voltage dividers: having reactive components, e.g. capacitive transformer
G01R 15/16
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: using capacitive devices
G01R 15/18
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: using inductive devices, e.g. transformers
G01R 19/16547
In AC or DC supplies: voltage or current in AC supplies