NERC TADS: Frequently Asked Questions

NERC | TADS Frequently Asked Questions | August 12, 2014

1

Preface

Table of Contents

Preface

Executive Summary

Chapter 1 – Questions and Answers

1.TADS Reporting, Generator Lead Lines, and Generators:

2.Lightning causes a line to trip. Line fails to auto-reclose as designed, causing the line to remain out for 10 minutes. Should the sustained cause be Lightning or Failed Protection System Equipment?

3.Clarification of “Normal Clearing”: If a breaker fails to trip from primary relaying but does successfully trip in the required time via secondary/backup relaying, is this considered normal or abnormal?

4.Trees washed out during flooding, slid down hill, and contacted line. Is the cause Environmental or Vegetation? [In the TADS definitions, flood seems to be a natural disaster that’s excluded from the vegetation cause code, so we’re thinking that the cause = Environmental]

5.See Figure 3 for the Following Questions:

6.For the following questions, refer to Figure 4:

7.Please see Figure 4 for the Following Questions:

8.Please see Figure 5 for the following questions:

9.Please see Figure 6 for the following questions:

10.For the following questions, refer to Figure 7:

11.For the following questions, refer to Figure 8:

12.FRCC TADS T.O. states that it would probably be of benefit if NERC included some examples in the next version of the TADS Manual that covers the rounding of outage durations. Example: An extended outage that lasts 1 min 27 seconds would be rounded down to 1 min when reported in TADS, whereas an outage of 1 min 56 seconds would be rounded up to 2 min in TADS.

13.Recently our group reviewed again some events and realized that the representation of the DC line with only two circuits was misleading because in fact we really have four sections, two per pole: X to Y (1000 km) and Y to Z (500 km). This is a complex system with several multiterminal and two-terminal configurations. We thought we could represent it as one section per pole but this leads to significant errors since the section length. This is a problem for automatic outages but will help a lot also the planned outages representation. We are not proposing to change it now since all the data are finalized for 2010 but we will like to rediscuss the representation for 2011. We understand that this will require to go back on previous years as well. We will be prepared to provide the data for other years with this new line model if you agree that this could be done.

14.Temporarily Jumpered AC Circuit

15.Momentary, then Less than 1 Minute Operational Outage

16.If a breaker trips for lightning and doesn't reclose because of an issue reclosing, this is NOT abnormal clearing. Is this correct?

17.Abnormal clearing has nothing to do with reclosing only tripping. Correct?

18.Also, if the system is set up to clear more than one line during a fault (and this is the expected result) even though it is not Normally set up this way (issue with breaker so two lines are being protected by single breaker), this would be Normal Clearing as well?

19.Operator Turns the Wrong Handle

20.A line correctly trips, and correctly recloses from one end. The other end of the line is designed to not reclose. If the operator closes the second end of the line back after more than one minute, what is the “Sustained Code”? There is no damage to the line, and the operator did not make an error. In the past, I was advised that this would be the same as the Outage Initiating Code. Is this correct?

21.A line correctly trips fails to reclose on one end due to a reclosing relay failure. What is the “Sustained Code”? Reclosing is no longer part of the NERC Glossary definition of Protection System. I feel like “Other” would be the most correct sustained code if we are following the document the way it is actually written, but “Failed Protection System” seems to follow the intent a little more.

22.NERC cannot force a Generator Owner (GO) to register as a Transmission Owner (TO) to report the transmission interconnections to the power grid. How should these transmission elements be handled?

23.Since the TADS reporting based new BES Definitions will begin January 1, 2015, will the Quarter 4 inventory data, normally submitted by the January 15, 2015 deadline, need to include the 100kV and above elements?

24.We had a circuit out for scheduled maintenance all day and it is entered in TADS as a planned outage. It was accidentally energized and closed/tripped. I believe it should be entered in TADS as a momentary outage. TADS will not let me enter it as an automatic outage since it is overlapping time with the planned outage. I was wondering what I should do.

25.Could you address an issue SERC and a few TOs are having with the Duration fields? TADS exports data to a CVS file format, but every Duration field does not translate well to the Excel environment. This necessitates a lot of manual interventions in order to normalize the data to a common format.

26.IMEA is registered as a TO in RF on behalf of an IMEA member with a 138 kV municipal system that serves only local distribution. IMEA will qualify for Exclusion 1 (Radial Systems) and Exclusion 3 (Local Networks) under the new BES Definition which becomes effective July 1, 2014; this will allow IMEA to deregister as a TO. If IMEA needs to take additional action, I would appreciate your advice

27.Could you address the training for TOs TADS reporting when we go to the BES TADS Elements? NERC Training of the regions last November had a slide showing that 2015 Q1 reporting would be for all BES TADS Elements.

28.TOs will need to be updating their system to accommodate the larger dataset and are enquiring into the training schedule. The sooner we have the data specifications delivered to the TOs, the better.

29.With the expanding scope of TADS reporting in 2015, will there be a significant change in the workbook to accommodate this reporting? If so, when an updated workbook will be available so that entities can begin compiling inventory data for sub-200 kV elements?

30.When we start reporting 161 kV information in 2015, will it be just Automatic (Unplanned) outages or both Non Automatic (Planned) and Automatic (Unplanned). Seems to me I heard that only Automatic outages will need to be entered for 161 KV. Also is there a site where I can get a summary of reporting requirements for 2015 or is it still in the works?

31.Should Form 3.4 be completed quarterly, or, is it a form that needs to be completed only in Q4?

32.Is the transformer with the arrow pointing to it TADS Reportable with the new BES alignment?

NERC | TADS Frequently Asked Questions | August 12, 2014

1

Preface

Preface

The North American Electric Reliability Corporation (NERC) is a not-for-profit international regulatory authority whose mission is to ensure the reliability of the bulk power system (BPS) in North America. NERC develops and enforces Reliability Standards; annually assesses seasonal and long‐term reliability; monitors the BPS through system awareness; and educates, trains, and certifies industry personnel. NERC’s area of responsibility spans the continental United States, Canada, and the northern portion of Baja California, Mexico. NERC is the electric reliability organization (ERO) for North America, subject to oversight by the Federal Energy Regulatory Commission (FERC) and governmental authorities in Canada. NERC’s jurisdiction includes users, owners, and operators of the BPS, which serves more than 334 million people.

The North American BPS is divided into several assessment areas within the eight Regional Entity (RE) boundaries, as shown in the map and corresponding table below.

NERC | TADS Frequently Asked Questions | August 12, 2014

1

Preface

Executive Summary

The purpose of this document is to provide a record of answers to questions that NERC staff has received on the NERC Transmission Availability Data System.

NERC | TADS Frequently Asked Questions | August 12, 2014

1

Chapter 1 – Questions and Answers

Chapter 1 – Questions and Answers

1.TADS Reporting, Generator Lead Lines, and Generators:

A.Are generator lead lines part of the Bulk Electric System?

It depends on the generator. (poor answer, research more) If the AC Circuit leads to a network comprising more than 75 MW of generator capacity, the AC Circuit is considered part of the BES. (research more)

B.Should they be reported in TADS?

All Bulk Electric System AC Circuits should be reported within webTADS.

C.In Scenario A, all the substations and transmission lines are 345kV. There is a 10 mile line/connection to a wind farm. This is considered a generator lead line at OG&E. For faults or planned outages, should the line/connection between substation B and the wind farm be reported in TADS? (Note: The wind farm trips offline due a SPS (Special Protection System) in place for faults between Substation A and Substation B.)

Figure 1: Scenario A

If the Wind Farm is at a total combined capacity above 75 MW, the generator lead line is considered part of the Bulk Electric System and should be reported in TADS.

D.In Scenario B, the gas unit plants sit adjacent to the 345kV substation. The gas units trip offline from time to time. In addition, they are taken offline for maintenance and load curtailment during the spring and fall seasons. Should Automatic and Planned outages on those lines be reported in TADS?

Figure 2: Scenario B

Based on the configuration shown, no Outages would be reported if the Gas Units on the right are tripped offline with the circuit breaker to its left. The Gas Units on the left would only result in a reportable Outage if either circuit breaker above or below it were operated. This is based on the definition of In-Service State that requires all terminals to be connected and energized.

[ADS1]

2.Lightning causes a line to trip. Line fails to auto-reclose as designed, causing the line to remain out for 10 minutes. Should the sustained cause be Lightning or Failed Protection System Equipment?

In the past, a recloser was considered part of the Protection System. However, with the new Protection System definition, the recloser is no longer considered part of the Protection System.

In this case, the DRI recommends to apply for the Sustained Cause Code the cause that “contributed to the longest duration of the Outage”. The recloser failing is the cause contributing the longest duration. Based on the AC Circuit boundary, the recloser could be considered within either the AC Circuit or AC Substation. It could be either Failed AC Circuit Equipment or Failed AC Substation Equipment based on the recloser’s location.

3.Clarification of “Normal Clearing”: If a breaker fails to trip from primary relaying but does successfully trip in the required time via secondary/backup relaying, is this considered normal or abnormal?

This is considered abnormal clearing according to the definitions. The Event should be coded as Event Type 61 (Dependability based).

4.Trees washed out during flooding, slid down hill, and contacted line. Is the causeEnvironmental or Vegetation? [In the TADS definitions, flood seems to be a naturaldisaster that’s excluded from the vegetation cause code, so we’re thinking that the cause= Environmental]

The Initiating Cause Code would be Environmental due to the flooding.

5.See Figure 3 for the Following Questions:

Figure 3: At substation B, 345 kV line A-B connects to 345 kV line B-C via PCB 123.

A.What is the terminal of Line A-B at substation B? SW122 or PCB123?

SW122, SW125 and PCB123 are considered the terminal for the line. SW122, SW125 and PCB123 must be connected for the AC Circuit to be considered In-Service.

This would not be the case if Substation B was in a breaker-in-a-half, double breaker, ring bus, or other multiple breaker situation. The terminal must comprise all switches and circuit breakers that would be necessary to allow power flow to cross the network into the AC Circuit.

B.What is the terminal of Line B-C at substation B? PCB123, SW124, or SW125?

SW122, SW125 and PCB123 are considered the terminal for the line. Both SW122, SW125 and PCB123 must be connected for the AC Circuit to be considered In-Service.

C.If PCB123 trips from low gas but both lines remain energized from their remote ends and SW 122, 124, and 125 remain closed, are Line A-B and Line B-C still in service?

According to the TADS definitions, Line A-B and Line B-C are not in an In-Service State. This is a case where the two AC Circuits are sharing a common terminal. The two Outages would both be Common Mode and have an Initiating Cause Code of Failed Protection System Equipment.

D.Assume that lightning strikes Line A-B and causes PCB123 to open. Line B-C remains energized from its remote end at Substation C. With PCB123 open, is Line B-C considered to be fully connected at Substation B? Is line B-C still in service, or has it been interrupted?

Because PCB123 is interrupted, the terminal connection is severed. Line B-C is no longer in an In-Service state.

E.If line B-C is considered to be interrupted in question #E, what is the outage mode? Dependent Mode or Common Mode?

The two Outages would both be Common Mode and have an Initiating Cause Code of Failed Protection System Equipment.

6.For the following questions, refer to Figure 4:

Figure 4: Line D-E is a 345 kV radial feeder circuit that supplies a 345 kV/138 kV transformer at Substation E.

A.Is there a terminal of Line D-E at substation E? If so, where does Line D-E end? SW3502, 3500CS, or PCB1510?

The terminal of AC Circuit D-E at Substation E would be comprised of SW3502 and 3500CS. Both must be connected in order for power flow to occur across the line from substation E. This would not be the case in a different bus configuration such as a radial bus, breaker-and-a-half, or double breaker configuration because power flow could still occur if some of the circuit breakers/switches were opened.

B.If Line D-E remains energized from Substation D, does opening 3500CS cause a TADS reportable interruption?

Opening 3500CS would disconnect the terminal consisting of SW3502 and 3500CS. This would cause an Automatic Outage of AC Circuit D-E.

C.If Line D-E remains energized from Substation D, does opening 3502 cause a TADS reportable interruption?

Opening SW3502 would disconnect the terminal consisting of SW3502 and 3500CS. This would cause an Automatic Outage of AC Circuit D-E.

D.If a transformer fault causes PCB1510 and 3500CS to open, is Line D-E still in service?

Opening SW3502 would disconnect the terminal consisting of SW3502 and 3500CS. This would cause an Automatic Outage of AC Circuit D-E.

Although Line D-E is reportable, everything forward of 3500CS going towards the Transformer is non-reportable because it is excluded from the Bulk Electric System. Please reference Exclusion E1 in

7.Please see Figure 4 for the Following Questions:

Figure 4: Power Plant P connects to the grid at Substation Q via the generation feeder circuit P-Q.

A.Is the feeder circuit P-Q considered a line for TADS purposes?

If the feeder AC Circuit P-Q is either completely or partially owned by an Entity with a Transmission Owner function, the Circuit should be reported for TADS purposes. TADS only applies to the Transmission Owner function.

B.If so, what are the terminals?

The terminals would be 3511 and 52-4. These two switches/breakers must be connected to ensure the AC Circuit can transfer power flow.

C.If the circuit remains energized and connected at Substation Q, does opening PCB 52-4 at Power Plant P cause an interruption?

Yes, the terminal at 52-4 would be disconnected. This would place the AC Circuit P-Q in a not In-Service State.

8.Please see Figure 5 for the following questions:

Figure 5: Line F-G is owned and operated by Company #1. Line G-H is owned and operated by Company #2.

Company #1 has registered Line F-G as a TADS Element. Company #2 has registered Line G-H as a TADS Element. There is no fault current interrupting device between Line F-G and Line G-H. When one line encounters a fault, both lines must trip in order to clear the fault.

A.Is Line F-G considered a separate line from Line G-H for TADS purposes?

Yes, Line F-G is considered a separate AC Circuit from Line G-H.

B.If so, what is the terminal for line F-G at Substation G? SW3424?

The terminal for line F-G is switch 2105 and switch 3424. Both must be connected for power flow to occur across the Element. Generally, the terminal can be determined from the minimal set or sets (in the case of a multiple breaker bus configuration) that must be connected for power flow to occur across the Element. This does not mean that the Element could not be deenergized from beyond its terminals.

C.If so, what is the terminal for line G-H at Substation G? SW3423?

The terminals for AC Circuit G-H would be SW3423 and SW3406. These switches must be connected for the AC Circuit to be considered In-Service. However, it could be confusing because the Circuit could be deenergized from beyond its terminals. For an AC Circuit to be considered In-Service for TADS, it must be both energized AND connected to all of its terminals. In many cases, it can be quicker to determine Outage reportablility by whether the Element is energized.

9.Please see Figure 6 for the following questions:

Figure 6: Line Q-R is a 345 kV circuit between Substation Q and Substation R. The line connects to a ring bus at Substation Q.

A.What is the terminal of Line Q-R at substation Q?

The terminal for Line Q-R at substation Q would comprise the switches/breakers: 3512, 3518E, 3518N, 3518, 3517S, 3517N and 3517. In determining this, you can see the 3 “sub-terminals” of: {3512}, {3518E, 3518N, 3518}, and {3517N, 3517S, and 3517}.The set of {3512} and the other two “sub-terminals” comprise the combined terminal. For a reportable TADS Outage to occur by disconnecting the terminal, {3512} AND BOTH OF the other two “sub-terminals” or both the sets containing 3517 and 3518 must be disconnected.

B.If PCB 3517 and PCB 3518 are open at Substation Q but line Q-R remains energized from Substation R and SW 3512 remains closed, is Line Q-R still in service?

Line Q-R is not considered in an In-Service state because both “sub-terminals” containing 3517 and 3518 had been disconnected. It is no longer possible for power flow to cross the Element.

C.What is the terminal of Line Q-R at substation R?

The terminal at substation R for Line Q-R would consist of the switches/breakers: 3457, 3454L, 3454 and 3454B.

D.Assume that all breakers and switches at Substation Q are closed and Line Q-R is energized from Substation Q. If PCB 3454 is opened at Substation R, but SW 3457 and SW 3454L remain closed, is Line Q-R still in service?