# US 9,435,835 B2 · Validation of electric power system monitoring systems

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- Number: US 9,435,835 B2
- Document ID: US9435835B2
- Status: Granted
- Kind: B2
- Application number: 13/335,547
- Filed: 2011-12-22
- Published: 2012-06-28
- Granted: 2016-09-06
- Earliest claimed: 2010-12-27
- Assignees: Schweitzer Engineering Laboratories, Inc.
- Applicants: Matthew B. Watkins; Normann Fischer; David M. Prestwich
- Inventors: Matthew B. Watkins; Normann Fischer; David M. Prestwich
- Web page: https://patentgrep.com/patent/US9435835B2

## CPC

- G01R 19/2513: {Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging}
- G01R 35/00: Testing or calibrating of apparatus covered by the other groups of this subclass
- Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y04S 10/18: using switches, relays or circuit breakers, e.g. intelligent electronic devices [IED]
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

The present disclosure provides systems and methods for validating electric power delivery monitoring systems, including, but not limited to, current transformers (CTs) and voltage potential transformers (PTs). According to various embodiments, a first IED monitors a portion of an electric power delivery system via one or more CTs and/or PTs. A second IED monitors the portion of the electric power delivery system via one or more additional CTs and/or PTs. Each IED may generate an event report, containing measurement data, associated with each respective measurement equipment. A validation module may compare the event reports in order to validate that the IEDs and/or the underlying measurement equipment are functioning correctly. According to various embodiments, the validation module may be configured to align the event reports from two IEDs using an event trigger common to both IEDs.

## Claims

### Claim 1

A system for validating a monitoring system of an electric power delivery system, comprising:
a first measurement equipment configured to generate a first signal corresponding to an electrical condition of the electric power delivery system;
a second measurement equipment configured to generate a second signal corresponding to the electrical condition of the electric power delivery system;
a monitoring system in communication with the first measurement equipment and the second measurement equipment, the monitoring system configured to:
receive the first signal from the first measurement equipment and generate a first set of measurement data; and
receive the second signal from the second measurement equipment and generate a second set of measurement data; and
a validation module configured to validate the functionality of the first measurement equipment relative to the second measurement equipment, the validation module configured to:
receive the first and second sets of measurement data;
align the first set of measurement data with the second set of measurement data, using a first event trigger generated from the first signal and a second event trigger generated from the second signal, such that the first and second sets of measurement data are aligned;
determine a reference quantity from the first set of measurement data at a first time along the aligned first and second sets of measurement data;
determine a comparison quantity from the second set of measurement data the first time along the aligned first and second sets of measurement data;
calculate an accuracy indication using a difference between the reference quantity and the comparison quantity; and
determine if the accuracy indication is within a predetermined threshold range of accuracy.

### Claim 2 (depends on 1)

The system of claim 1, wherein the validation module is configured to provide an alert when the accuracy indication is outside of a predetermined threshold accuracy range.

### Claim 3 (depends on 1)

The system of claim 1, wherein the first measurement equipment comprises a first current transformer and the second measurement equipment comprises a second current transformer.

### Claim 4 (depends on 1)

The system of claim 1, wherein the first measurement equipment comprises a first potential transformer and the second measurement equipment comprises a second potential transformer.

### Claim 5 (depends on 1)

The system of claim 1, wherein the reference quantity from the first set of measurement data comprises a phasor magnitude and angle corresponding to the first set of measurement data at the first time, and
wherein the comparison quantity from the second set of measurement data comprises a phasor magnitude and angle corresponding to the second set of measurement data at the first time.

### Claim 6 (depends on 1)

The system of claim 1, wherein the monitoring system comprises:
a first intelligent electronic device (IED) in communication with the first measurement equipment, the first IED configured to receive the first signal from the first measurement equipment and generate the first set of measurement data; and
a second IED in communication with the second measurement equipment, the second IED configured to receive the second signal from the second measurement equipment and generate the second set of measurement data.

### Claim 7 (depends on 6)

The system of claim 6, wherein the validation module is integrated within one of the first and second IEDs, and
wherein the first and second IEDs are in communication with one another.

### Claim 8 (depends on 6)

The system of claim 6, wherein the validation module is integrated within a validation device in communication with the first and second IEDs.

### Claim 9 (depends on 6)

The system of claim 6, wherein the first event trigger is common with the second event trigger.

### Claim 10 (depends on 9)

The system of claim 9, wherein the first event trigger and the second event trigger are generated by an external source and provided to each of the first IED and the second IED.

### Claim 11 (depends on 9)

The system of claim 9, wherein the first event trigger is automatically generated by the first IED and the second event trigger is automatically generated by the second IED in response to a change in the electrical condition in the electric power delivery system.

### Claim 12 (depends on 11)

The system of claim 11, wherein the first and second event triggers are automatically generated in response to the detection of one of an overcurrent, an undercurrent, a overvoltage, voltage drop, overfrequency, underfrequency, and change in frequency.

### Claim 13 (depends on 1)

The system of claim 1, wherein the monitoring system comprises the first measurement equipment and the second measurement equipment.

### Claim 14

A method for validating a monitoring system of an electric power delivery system, comprising:
generating a first signal corresponding to an electrical condition of the electric power delivery system using a first measurement equipment;
generating a second signal corresponding to the electrical condition of the electric power delivery system using a second measurement equipment;
receiving the first signal from the first measurement equipment and generating a first set of measurement data using a monitoring system;
receiving the second signal from the second measurement equipment and generating a second set of measurement data;
receiving, by a validation module, the first and second sets of measurement data;
generating a first event trigger from the first signal;
generating a second event trigger from the second signal;
aligning the first set of measurement data with the second set of measurement data using the first event trigger and the second event trigger, such that the first and second sets of measurement data are aligned;
determining a reference quantity from the first set of measurement data at a first time along the aligned first and second sets of measurement data;
determining a comparison quantity from the second set of measurement data the first time along the aligned first and second sets of measurement data;
calculating an accuracy indication using a difference between the reference quantity and the comparison quantity; and
determining if the accuracy indication is within a predetermined threshold range of accuracy.

### Claim 15 (depends on 14)

The method of claim 14, further comprising the validation module providing an alert when the accuracy indication is outside of a predetermined threshold accuracy range.

### Claim 16 (depends on 14)

The method of claim 14, wherein the first measurement equipment comprises a first current transformer and the second measurement equipment comprises a second current transformer.

### Claim 17 (depends on 14)

The method of claim 14, wherein the first measurement equipment comprises a first potential transformer and the second measurement equipment comprises a second potential transformer.

### Claim 18 (depends on 14)

The method of claim 14, wherein determining a reference quantity from the first set of measurement data comprises determining a phasor magnitude and angle corresponding to the first set of measurement data at the first time, and
wherein determining a comparison quantity from the second set of measurement data comprises determining a phasor magnitude and angle corresponding to the second set of measurement data at the first time.

### Claim 19 (depends on 14)

The method of claim 14, wherein the monitoring system comprises:
a first intelligent electronic device (IED) and a second IED, and
wherein receiving the first signal from the first measurement equipment and generating the first set of measurement data is performed by the first IED, and
wherein receiving the second signal from the second measurement equipment and generating the second set of measurement data is performed by the second IED.

### Claim 20 (depends on 19)

The method of claim 19, wherein the validation module is integrated within one of the first and second IEDs, and
wherein the first and second IEDs are in communication with one another.

### Claim 21 (depends on 19)

The method of claim 19, wherein the validation module is integrated within a validation device in communication with the first and second IEDs.

### Claim 22 (depends on 19)

The method of claim 19, wherein the first event trigger is common with the second event trigger.

### Claim 23 (depends on 22)

The method of claim 22, wherein the first event trigger and the second event trigger are generated by an external source and provided to each of the first IED and the second IED.

### Claim 24 (depends on 22)

The method of claim 22, wherein the first event trigger is automatically generated by the first IED and the second event trigger is automatically generated by the second IED in response to a change in the electrical condition in the electric power delivery system.

### Claim 25 (depends on 24)

The method of claim 24, wherein the first and second event triggers are automatically generated in response to the detection of one of an overcurrent, an undercurrent, a overvoltage, voltage drop, overfrequency, underfrequency, and change in frequency.

### Claim 26 (depends on 14)

The method of claim 14, wherein the monitoring system comprises the first measurement equipment and the second measurement equipment.

### Claim 27

A system for validating a monitoring system of an electric power delivery system, comprising:
a monitoring system in communication with the electric power delivery system configured to:
obtain a first signal corresponding to an electrical condition of the electric power delivery system and generate a first set of measurement data therefrom; and,
obtain a second signal corresponding to an electrical condition of the electric power delivery system and generate a second set of measurement data therefrom;
generate a first event trigger from the first signal;
generate a second event trigger from the second signal;
a validation module in communication with the monitoring system, and configured to:
receive the first and second sets of measurement data;
align the first and second sets of measurement data using the first and second event triggers, wherein the first and second event triggers correspond to an event common to the first and second sets of measurement data; and,
calculate an accuracy indication using the aligned first and second sets of measurement data.