Draft Copy for Review Use Only

DRAFT COPY FOR REVIEW USE ONLY

Includes Comments from 9/1724 ROS/Telemetry Standards Workshop

Reliant Energy Comments – September 28, 2007

Texas Nodal Market

Telemetry Criteria

Version0.08576

August 27September 24, 2007

Telemetry Standards

Telemetry Status and Analog Measurements Data

A.Introduction[EC1]

ERCOT TAC [EC2]TAC is charged by the Nodal Protocol 3.10.7. 45 to create Telemetry Criteria. This Telemetry Criteria document specifies the Telemetry Criteria called for in the Nodal Protocols. TAC approves the Telemetry Criteria and an appropriate TAC subcommittee is required to update the Telemetry Criteria annually each October or more often on a periodic basis as deemed necessary.

Acquisition of good (VALID) telemetry status and analog measurements data (Telemetry) for of the transmission power system (System) together with an accurate power system model of the system are processed by a state State estimator Estimator to provide an optimal estimate of the System power system state at a given point in time while filtering measurement noise (error) and detecting gross errors. The quality and availability of telemetry provided to ERCOT are important to the performance of the ERCOT State Estimator and LMP and price calculations as well as other the LMP calculationsall ERCOT Real-time applications. As directed by the Nodal Protocols, these Telemetry Criteria are designed to ensure proper performance of the aforementioned applications[EC3].

Telemetry is not needed at every node of the System to arrive at a good estimate of the System’s state. There are general telemetry performance criterion, such that sufficient numbers and placement of measurements and accuracy of measurements that are available to achieve System observability and an overall good State Estimator performance.

Beyond general telemetry performance criterion there are more stringent criterion needed at locations where state estimates are “critically important” (e.g., locations where reliability, security, and Market impact are of more focused concern).

In case of a conflict between these Telemetry Criteria and the Nodal Operating guide and or the Nodal Protocols, the Nodal Protocols shall prevail.

Required Telemetry

Telemetry of Voltage and Power Flow

Each TSP shall provide telemetered measurements on modeled Transmission Elements to ensure State Estimator observability of any monitored voltage and power flow between their associated transmission breakers to the extent such can be shown to be needed in achieving the TAC-approved SE performance standard. On monitored non-Load substations, each TSP shall install, at the direction of ERCOT, sufficient telemetry such that there is an “N-1 Redundancy.” An N-1 Redundancy exists if the flow remains observable on the loss of any single measurement pair (MW, MVAr) excluding station RTU communication path failures. In making the determination to request additional telemetry, ERCOT shall consider the economic implications of inaccurate representation of Load Models in LMP results versus the cost to remedy.

QSEs, Resources and TDSPs are required to provide power operation data to ERCOT including, but not limited to:

(1)Real time generation data from QSEs;

(2)Planned Outage information from Resources;

(3)Network data used by any TDSP’s control center, including:

(a)Breaker and line switch status of all ERCOT Transmission Grid devices;

(b)Line flow MW and MVAR;

(c)Breaker, switches connected to all Resources;

(d)Transmission Facility Voltages; and

(e)Transformer MW, MVAR and TAP.

(4)Real time generation and Load acting as a Resource meter data from QSEs;

(5)Real time Generation meter splitting signal from QSEs;

(6)Planned Transmission Outage information from TDSP;

(7)Network transmission data (model and constraints) from TDSP; and

(8)Dynamic Schedules from QSEs;

Real Time data will be provided to ERCOT at the same scan rate as the TDSP or QSE obtains the data from telemetry.

B.Requirements

B.1.Operations Requirements

R1.Telemetry of Breaker and Switch Status [NP: 3.10.7.45.1(1[EC4]))]

Continuous Telemetry of the Status of Breakers and Switches

Each TSP and QSE shall provide telemetry, as described in this subsection, to ERCOT on the status of all breakers and switches used to switch any Transmission Element or load modeled by ERCOT. Each TSP and QSE is not required to install telemetry on individual breakers and switches, where the telemetered status shown to ERCOT is current and free from ambiguous changes in state caused by the TSP or QSE switching operations and TSP or QSE personnel. Each TSP or QSE shall update the status of any breaker or switch through manual entries, if necessary, to communicate the actual current state of the device to ERCOT, except if the change in state is expected to return to the prior state within one minute. If in the sole opinion of ERCOT, the manual updates of the TSP or QSE have been unsuccessful in maintaining the accuracy required to support State Estimator performance to the State Estimator Performance Standard, ERCOT may request that the TSP or QSE install complete telemetry from the breaker or switch to the TSP or QSE, and then to ERCOT. If the TSP disputes the request for additional telemetry the TSP shall have the appeals process available under the section titled “ERCOT Requests for Telemetry”R14 or R15 as applicable. In making the determination to request installation of additional telemetry from a breaker or switch, ERCOT shall consider the economic and reliability implications of inaccurate representation of Model Loads in LMP resultsLMP resultsERCOT Real-time applications versus the cost to remedy.[ the above is quoted directly from the protocols and should not be changed]

General Telemetry Performance Criteria

The following criterion will apply in general to Telemetry provided to ERCOT:

R2.Required TSP Telemetry [NP: 3.10.7.45.2(3)][1]

TSPs are required to provide power operation data to ERCOT as defined in the ERCOT Nodal Protocols. Each TSP shall provide telemetered measurements on modeled Transmission Elements to ensure State Estimator observability of any monitored voltage and power flow between their associated transmission breakers needed in achieving the TAC-approved State Estimator performance standard. On monitored non-Load substations, each TSP shall install, at the direction of ERCOT, sufficient telemetry such that there is an “N-1 Redundancy.” An N-1 Redundancy exists if the flow remains observable on the loss of any single measurement pair (MW, MVAR) excluding station communication path failures.

• TSPs are required to provide power operation data to ERCOT as defined in the ERCOT Protocols and Nodal ICCP Communication HandbookNodal Operating Guides. ERCOT will monitor the validity of the Network Model as it affects State Estimator results in order to determine additional required data[EC5].

(1)The TSP shall maintain the sum of flows into any telemetered bus less than the greater of 5 MW or 5% of the largest line rating at each bus.

(2)Each QSE or TDSP shall provide data to ERCOT that meets the following availability:

Ninety eight (98%) percent of all telemetry provided to ERCOT must achieve a quarterly availability of eighty (80%) percent. Availability will be measured based on end-to-end connectivity of the communications path and the passing of Real-Time data with good quality codes at the scheduled periodicity.

Non-TSP substation owners shall provide the required data to their interconnected TSP as defined byin accordance to new construction and redundancy requirements set forth in R14 and R15.TDSPTSP’s shall make reasonable efforts to obtain this the required data from retail customers associated with new customer-owned substations as defined by requirements R14 and R15.to meet this standard or obtain agreement from ERCOT that these retail customers have entered into arrangements with ERCOT to provide this data to ERCOT. If the data cannot be obtained under either of these methods, ERCOT shall report such cases to the Wholesale Electric IndependentWholesale Electric Market Monitor (WEMM).

R3.Required QSE Telemetry [NP: 6.5.5.2(2)]1

QSEs are required to provide power operation data to ERCOT as defined in the ERCOT Nodal ICCP Communication HandbookProtocols. The data exchange tables in that document represent all potential data required.

R4.Telemetry Scan Rates [NP: 3.10.7.5(3)][2]

ERCOT will scan QSE and TSP data at scan rates as defined in the ERCOT Nodal Protocols and the ERCOT Nodal Operating GuideICCP Communication Handbook. The data exchange tables in that document specify the frequency of scan rates to be used within ERCOT. Data acquired through field telemetry shall be made available to ERCOT through the least number of intermediate systems possible. In no case shall field telemetered data be delayed beyond the specified scan rates due to a point’s propagation through one or more intermediate systems.[EC6]

The telemetry provided to ERCOT by each TSP must be updated at a 10 second or less scan rate and be provided to ERCOT at the same rate. Each TSP and QSE shall install appropriate condition detection capability to notify ERCOT of potentially incorrect data from loss of communication or scan function. Condition codes must accompany the data to indicate its quality and whether the data has been measured within the scan rate requirement.

R5.Data Quality[3]

Market Participant’s shall provide documentation to ERCOT describing their native system quality codes and defining the conversion of their quality codes into the ERCOT defined ICCP quality codes consistent with the ERCOT Nodal Operating GuideICCP Communication Handbook[EC7].

B.2.Maintenance Requirements

R6.Minimum Telemetry Criteria [NP: 3.10.7.5.2(5)]

The TSP or QSE[EC8] shall assist ERCOT in maintaining the algebraic sum of the telemetered measurements around each Electrical[EC9]substation buss such that they are less than 5% of the largest normal line rating or 5 MW, whichever is greater.

R7.Telemetry Availability[4]

All points made available to ERCOT must achieve a monthly calendar quarterly availability of ______[EC10] (__8099%) percent. Availability will be measured based on end-to-end connectivity of the communications path and the passing of Real-Time data with VALID quality codes at the scheduled periodicity. [EC11][ 80% allows data to be out of service for over 18 days in a calendar quarter; % availability must be at least consistent with Good Utility Practice.]

[EC12]

Where:

A =average percent availability of all points received from a given QSE or TSP.

T =total number of seconds in the monthquarter.

i =the ith point having a quality code other than VALID

n =total number of points having a quality code other than VALID

Bi =number of seconds during the monthquarter that the ith point had quality other than VALID.

*Exceptions to Telemetry Availability calculation inputs:

• ERCOT declared eEmergency Notice that can effect telemetry
• Total failure of the ERCOT supplied WAN communication system problems
• 3rd party communication problems [TSPs and QSEs must contract with 3rd parties to provide service to meet this standard; such is not under the control of ERCOT nor other MPs effected by the failed communication system]

R8.Locally and Remotely Replaced Telemetry

In the event that ERCOT identifies an individual Valid telemetered value which it believes is incorrect, it shall notify the providing entity, and direct them to manually replace the erroneous data until the error is corrected.

ERCOT will not manually replace telemetry status or analogs from TSP’s or QSE’s unless the TSP or QSE notifies them that they are technically incapable of performing a manual replace function due to technical difficulties at their facility except in emergency situations as deemed by the ERCOT shift supervisor. In this event, ERCOT shall notify market participants thru the Event Notification System (ENS) until the technical difficulty is resolved.[EC13]

Telemetry remotely replaced by TSP or QSE will be reported to the responsible entityowner. When requested by ERCOT, TSP and QSE shall provide ERCOT with a plan within 12 Business dDay for fixing [EC14] remotely replaced telemetry[EC15].[EC16]

Exceptions to the General Telemetry Performance Criterion shall be made for data points not significant in the solution of the State Estimator or required for the reliable operation on the ERCOT Transmission System. Some examples of these are:

(a)Substation with no more than two transmission lines and less than 10 MW of load;

(b)Connection of Loads along a continuous, non-branching circuit that may be combined for telemetry purposes;

(c)Substations connected radially to the bulk transmission system.

R9.Critically Important Telemetry[EC17][EC18][5]

Critically Important Telemetry Performance Criterion

ERCOT will identify MW/MVAR Telemetry pairs, not exceeding 10% of the Transmission Elements in ERCOT, and voltage points that are “critically important” to reliability, to system, generation, and load observability, to support of State Estimator performance, or are of a commercial Market concern. ERCOT will identify MW/MVAR Telemetry pairs, not exceeding 10%[EC19] of the Transmission Elements in ERCOT, critical measurements[6] and 20 voltage points that are “critically important” to reliability, system observability[EC20], support of State Estimator performance, or are of a the commercial Market concern. This critically important telemetry will be considered “Critically Important Telemetry” in the context of this document. must meet more stringent criterion for accuracy and availability where specifically addressed. ERCOT will review and publish this list annually.

ERCOT will use the following criterion criteria [EC21]to identify critically important Telemetry:

(1)Telemetry necessary to meet the requirements of the protocols.

(2)Loss of a telemetry point that results in the inability of ERCOT to monitor loading on a transmission line operated at 345 kV or above.

(23)Loss of a telemetry point that results in the inability of ERCOT to monitor loading on a 345/138 kV autotransformer.

(34)Loss of a telemetry point that results in the inability of ERCOT to monitor the loading on transmission facilities designated as critically important to transmission reliability by ERCOT. A list of critical facilities will be published annually.

(45)Telemetry necessary to monitor transmission elements identified as causing 80% of congestion cost in the year for which the most recent data is available.

R1.(56)Telemetry necessary to monitor the 20 most voltage critical buses designated by ERCOT and approved by TAC each October.[EC22]

R10.Availability for Critically Important Telemetry[7]

All critical points made available to ERCOT by each QSE or TSP must achieve a monthly availability of ___% [EC23]percent or better. Availability will be measured based on end-to-end connectivity of the communications path and the passing of Real-Time data with VALID ICCP quality codes at the scheduled periodicity.All Critically Important Telemetry points made available to ERCOT must achieve a calendar quarterly availability of 909% percent. Availability will be measured based on end-to-end connectivity of the communications path and the passing of Real-Time data with VALID quality codes at the scheduled periodicity. [EC24]

1

Where:

A =average percent availability of all points received from a given QSE or TSP.

T =total number of seconds in the quarter.

i =the ith point having a quality code other than VALID

n =total number of points having a quality code other than VALID

Bi =number of seconds during the quarter that the ith point had quality other than VALID.

Exceptions to Telemetry Availability calculation inputs:

• ERCOT declared eEmergency Notice that can effect telemetry

• Total failure of the ERCOT WAN supplied communication problems system

3rd party communication problems[cd25]

Each[EC26] QSE or TDSP shall provide data to ERCOT that meets the following availability:

Ninety five (95%) percent of the critically important telemetry defined by ERCOT must achieve a quarterly availability of ninety (90%) percent. Availability will be measured based on end-to-end connectivity of the communications path and the passing of Real-Time data with valid or manual quality codes at the scheduled periodicity.

R11.Restoration of Failed Telemetry and repair of inaccurate telemetry

TDSP/QSE Telemetry Restoration

Telemetered data shall be provided continuously at the scan rates specified herein. Lost data or signals, whether failed or in error, must be restored promptly by the provider of the telemetered data. It is recognized that some data may be more critical that than other data. ERCOT will inform the TDSPTSP or QSE if a data item is critical and needs to be repaired as quickly as possible. QSE and TDSPTSP repair procedures and records shall be made available to ERCOT upon request.

Before ERCOT requests review/re-calibration of a problem piece of equipment it shall discuss the problem with the provider to attempt to arrive at a consensus decision on the most appropriate action.

When ERCOT notifies a data provider of a data element which is providing telemetry data inconsistent with surrounding measurements, the provider shall, within 30 days, either a) Calibrate/repair the mis-behaving equipment b) Request an outage to schedule calibration/repair of the mis-behaving equipment c) Provide ERCOT with a plan to re-calibrate or repair the equipment in a reasonable time frame or d) Provide ERCOT with engineering analysis proving the data element is providing accuracy within its specifications. Before ERCOT requests review/re-calibration of a problem piece of equipment it shall discuss the problem with the provider to attempt to arrive at a consensus decision on the most appropriate action. [EC27]

When ERCOT notifies a data provider of a data element which is providing telemetry data inconsistent with surrounding measurements, the provider shall, within 30 days, either

1) Calibrate/repair the malfunctioning equipment

2)Request an outage to schedule calibration/repair of the malfunctioning equipment

3)Provide ERCOT with a plan to re-calibrate or repair the equipment in a reasonable time frame or

4)Provide ERCOT with engineering analysis proving the data element is providing accuracy within its specifications.

Calibration, Quality Checking and Testing

R12.Calibration, Quality Checking and Testing

It is the responsibility of the owner [EC28]either TSP or QSE [EC29]to insure that calibration, testing and other routine maintenance of equipment is done on a timely basis , and that accuracy meets or exceeds that which is specified in this Appendixconsistent with Good Utility Practice, for both the overall system and for individual equipment where detailed herein.