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ERCOT Nodal ProtocolsTelemetry Requirements Proposal

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Telemetry Proposal

• 100% of switches/breakers status telemetered to ERCOT (protocol)• Accuracy of telemetry is identified to ERCOT:

– PT Accuracy– CT accuracy– Transducer accuracy– A/D converter accuracy

For 100% of analog measurements.

• QSE/TSP provides ERCOT with a calibration plan which either guarantees calibration every 2 years (minimum) or provides an analysis which guarantees less than 1% of analogs will move outside the specified accuracy range each year.

• QSE/TSP re-calibrates telemetry identified by ERCOT as suspect within 2 working days; or respond with analysis of how the user has established it remains accurate without calibration to ERCOT satisfaction.

• QSE/TSP documents to ERCOT the analog and quality codes associated with each RTU, and documents for ERCOT the logic used to convert that data and quality code into ICCP data provided to ERCOT.

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Telemetry Proposal

• Status & analogs telemetered to ERCOT will be identified with the following status codes:– Valid – represents analog or status less then 10 seconds old, received from field– Manual – represents a analog or status entered manually at the market participant (not received from the field

electronically)– Stale – Represents a analog or status received electronically from the field which is over 10 seconds old; but less

than 10 minutes old.– Suspect - Represents a analog or status received electronically from the field which is over 10 minutes old.– Invalid – Represents a analog or status which the market participant has identified as out of reasonability limits.– Com_fail – informs ERCOT that due to communications failure, the analog or status provided ERCOT is not valid.– The market participant will document to ERCOT of what status combinations are valid

• TSP telemetries analogs will be available and valid at ERCOT 99% of time on a monthly basis. ERCOT will produce monthly report.

• Each individual TSP telemetry analog will be available and valid at ERCOT 80% of time on a monthly basis.

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Proposal -Metrics

• QSE/TSP performance Metrics

– Status of 99.95% of switches/breakers identified as ICCP points – Measured by number of ICCP status points divided by the number of switches/breakers modeled in ERCOT database.

– Example:

TSP_A has 6,000 switches and breakers status telemetered to ERCOT. The ERCOT model has 6,030 switches and breakers modeled and identified as belonging to that TSP. TSP_A has 6000/6030 = .99502 or 99.502% of switches and breakers status telemetered to ERCOT and fails this metric.

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Proposal -Metrics

• QSE/TSP performance Metrics

– Analogs defined as available to ERCOT in database are valid or manual to ERCOT 99% of time in each month – Measured by summing 5 minute samples valid (by QSE/TSP) divided by number defined (by QSE/TSP)

– Example:

QSE_B has 500 telemetered analog measurements. During a month, these 500 telemetered analogs were sampled for state estimator (5 minute sample) 8640 times each; during which 431,856 had a quality code of “valid” or “manual”. The performance is 431,856/(500*8640) = 431,856/432,000=.99966. The QSE passes this metric.

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Proposal -Metrics

• TSP performance Metrics

– 99.8% of individual analogs defined as available to ERCOT in database is valid at ERCOT >80% of time in a month – measured by number of points with valid >80% of 5 minute samples in a month divided by total number of analogs defined on 1st day of month.

– Example:

During a month TSP_C has 13,000 valid analog measurements on the 1st day of the month. During the month 8640 samples are used by state estimator. 183 analog measurements have over 1728 samples taken during which there status was not valid. TSP_C has (13,000-183)/13,000 = 98.59% analogs available; which fails this metric.

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Proposal -Metrics

• QSE/TSP performance Metrics

– TSP has 2 independent ICCP data links to ERCOT with hot standby and automatic failover available at least 95% of the time. If a backup fails the provider has 24 hours to respond to the failure. If both the primary and backup fail the provider is obligated to have technical personnel responding to the failure within 2 hours.

– TSP has responded to telemetry calibration requests within 2 work days 90% of time with calibration results. – Measured by ERCOT report quantifying number of requests responded to within 2 work days divided by total number of requests made in a 3 month period.

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Key Points

• ERCOT – Notify TSP recalibration required whenever residual > 5% of line rating over 25% of time for any given week. (i.e. 504 violations any given week – 7 days) use SE procedure of monitoring of accuracy classes by SE

• TSP response (i.e. calibration) required within 48 working

hours (i.e. 2 work days)

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ERCOT Obligation TSP Obligation Logic

 Provide telemetry to ERCOT on the status of all

breakers and switches  

 Identify expected accuracy of telemetry

supplied to ERCOT.Needed to properly assign weighting factors to

telemetry

 

Service telemetry and provide written report to ERCOT on re-calibration within 2 working days. Required to achieve SE telemetry standard

 

Install ERCOT required telemetry within 12 months or provide written plea to PUCT that the request is unreasonable.  

 

Identify to ERCOT the value and quality codes supplied by each RTU, and document the processes converting that data and quality coding into ICCP data provided to ERCOT  

TSP has a plan to calibrate telemetry on an annual basis or an alternate plan that guarantees < 1% out of calibration

Identify Telemetry suspected of operating outside expected accuracy range through state estimator    

Identify additional telemetry required to meet State Estimator observability or redundancy standard    

Perform monthly analysis of Telemetry performance by TSP and provide to TSP & post    

Notify Compliance of repeated failure of TSP to meet telemetry obligations after 3 months.    

ERCOT shall implement monitor programs to identify failure of market participant telemetry systems.

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Objections