Download Stakeholder Comment and Reply Matrix AESO AUTHORITATIVE DOCUMENT PROCESS

Stakeholder Comment and Reply Matrix
AESO AUTHORITATIVE DOCUMENT PROCESS
Proposed New ISO Rules Section 502.3 Interconnected Electric System Protection Requirements (“New ISO Rules Section 502.3”)
Date of Request for Comment [yyyy/mm/dd]:
Period of Consultation [yyyy/mm/dd]:
2012/08/14
2012/08/14
through 2012/09/14
1. ISO Rules
(a) Purpose of Proposed New ISO Rules Section 502.3
Proposed New ISO Rules Section 502.3 sets out the minimum technical protection
system requirements for the interconnected electric system.
In developing the New ISO Rules Section 502.3 the AESO has redrafted and
relocated content from the current AESO Protection Standard. In addition, in
developing New ISO Rules Section 502.3 the AESO is proposing changes as
outlined below, as a result of the review performed with the industry workgroup.
In the AESO’s opinion, these proposed changes improve the protection systems on
the Alberta interconnected electric system and ultimately the safe reliability
operation of the system.
The AESO is specifically seeking comments from stakeholders with respect to these
key changes. Please provide comments on :
1) Do you agree or disagree that the AESO has clearly and adequately
represented the key changes in proposed New ISO Rules Section 502.3? If
you disagree please provide your reasons and suggestions for improvement.
Stakeholder Comments and/or Alternate Proposal
AESO Replies
EDTI
1.
With regards to Subsection 15, EDTI requests
clarification as to whether there are any timing
(speed) requirements, similar to those provided in
Subsection 8, with isolating faults with 5 ohms
ground fault resistance. EDTI has a number of
very short lines (2-10 ohms line impedance) and in
some cases 5 ohms arc resistance can only be
detected by distance protection with zone 2 and
using communications. Alternatively the same fault
can be tripped by the line differential relay.
1. In the AESO’s opinion, draft Information
Document # 2012-004R Protection System
information (“ID 2012-004R”) provides the
clarification that EDTI is seeking. Specifically,
Section 8.1 in draft ID# 2012-004R states:
“For further clarity, the required protection relay
operate times identified in subsection 7 are not
intended to be applied in conjunction with the five
(5) ohm impedance. Slower clearing times for
ground faults are acceptable as they do not cause
stability issues.”
In addition, proposed New ISO Rules Section
502.3 applies to new facilities as referenced in
future project specification and is not intended to
apply retroactively.
Accordingly, the AESO has not amended final
proposed New ISO Rules Section 502.3 to provide
further clarification.
AESO Replies to Stakeholder Comments: 2012-10-23
Page 1 of 10
2.
In Subsection 16(1)(b), EDTI believes the correct
wording should read “not allow for more than one
(1) attempt at each end of the line to auto-reclose
the bulk transmission line”
2. The AESO agrees with EDTI’s suggestion, and
accordingly, has amended final proposed New
ISO Rules Section 502.3.
In addition, AESO review identified that Section
8.2 of ID# 2012-004R, incorrectly referenced
subsection 17 of proposed New ISO Rules
Section 502.3. Accordingly, the AESO amended
Section 8.2 of draft ID# 2012-004R to correctly
reference subsection 16 of proposed New ISO
Rules Section 502.3.
3.
With regards to Subsection 21(2), EDTI would like
to comment that upon communications failure, the
line differential function must be blocked. For the
relay to still detect and trip, the relay should be of a
hybrid design, and the trip is done by distance
element without communications. EDTI believes it
would be adequate to include this information in the
Information Document.
4.
EDTI recommends that Subsection 29(1)(a) should
read, “one(1) independent overcurrent protection
system installed on the high voltage side;”
If the high voltage side is not mentioned, some
entities may install one overcurrent on the low
voltage side and the transformer will have no
redundant protection against internal faults.
3.
The AESO agrees with EDTI’s suggestion and
has amended draft ID# 2012-004R accordingly.
4. The AESO agrees with EDTI’s suggestion for
transformers less than 25MVA in size as the
overcurrent is intended to provide redundant
protection. For larger transformers the location of
the overcurrent protection is not as important as
the transformer is protected by redundant
differential protections.
Accordingly, the AESO has amended final
proposed New ISO Rules Section 502.3
subsection 29.
5.
Transformers must be protected against (1) internal
faults, (2) dangerous through current in case of
external faults and (3) overload conditions.
For internal faults a differential protection and an
overcurrent protection (50/51) installed on the high
voltage winding are usually used. If strong infeed
5. For larger transformers two differentials are
required to ensure all internal transformer faults
are cleared high speed.
The overcurrent element was intended to provide
backup coverage for external faults. As written
29(2)(b) indicates the overcurrent should be on
AESO Replies to Stakeholder Comments: 2012-10-23
Page 2 of 10
exist from the low voltage side one directional
overcurrent (67) relay connected to the low voltage
winding is used.
the secondary side and is only needed to detect
overloads.
The use of directional overcurrent would also
meet the intent of this requirement.
For dangerous through faults an overcurrent
protection (51) installed on the high voltage winding
or a low voltage overcurrent protection (51)
installed on the low voltage winding are used.
Accordingly, subsection 29 of final proposed New
ISO Rules Section 502.3, has been amended to
allow overcurrent on either the high or low
voltage side for large transformers and will be
broadened to cover through faults other than
overloads.
The low voltage (51) is not design to detect internal
faults.
1. Clarified applicability and the relationship of proposed New ISO
Rules Section 502.3 to a project’s Functional Specification will
be provided.
Subsections
1 to 5
AltaLink Management Ltd
6.
AltaLink supports with language suggestions.
6.
AltaLink recommends that the wording “functional
specification” be adjusted to “initial (i.e., first issue)
functional specification” in section 2 and subsection
3(1) to provide further clarity.
The AESO disagrees with AltaLink’s language
suggestions. As projects are developed revisions
to functional specifications are made. The final
functional specification issued supercedes earlier
versions.
Accordingly, the AESO has not amended final
proposed ISO Rules Section 502.3.
7.
AltaLink recommends that more details be provided
regarding the application of the Rule on existing
facilities. Although the application of the Rule on
existing facilities is discussed in the Information
Document, it is not clear how the AESO will define
in the functional specification (as it is not clear in
the Rule) when existing facilities need to meet the
requirements of the new Rule.
7.
The AESO disagrees with AltaLink that more
details are required regarding the application of
proposed ISO Rules Section 502.3 on existing
facilities. The AESO’s project functional
specifications are typically for the addition of new
facilities and will reference final proposed ISO
Rules Section 502.3 that need to be complied
with by these new facilities. For new standalone
“green field” facilities, all such facilities need to
meet final proposed ISO Rules Section 502.3.
For the addition of new facilities in existing
substations, these new facilities will need to meet
final proposed ISO Rules Section 502.3.
However, integrating the new facilities into the
existing substation may require changes to
existing protection systems. Consistent with
current practices, modifications to existing
AESO Replies to Stakeholder Comments: 2012-10-23
Page 3 of 10
facilities will be determined on a case-by-case
basis and if modifications to existing facilities are
required the AESO will indicate this in the
functional specification.
Accordingly, the AESO has not amended final
proposed ISO Rules Section 502.3.
8.
Subsection 1(c) states that the rule applies to “the
legal owner of a transmission facility with a rated
voltage equal to or greater than one hundred (100)
kV;…” However, the rule does not indicate if it only
applies to facilities connected at 100 kV or higher?
AltaLink recommends that the rule include a
statement that indicates that it applies to
transmission facilities with a rated voltage equal to
or greater than one hundred (100) kV.
8.
The AESO disagrees with AltaLink’s language
suggestions. The “applicability” section in
proposed ISO Rules Section 502.3 is consistent
with drafting of applicability sections in other ISO
rules and Alberta Reliability Standards. Some
examples include:
1. ISO Rules Section 502.2 Bulk Transmission
Line Technical Requirements
2. Alberta Reliability Standard PRC–021–AB–1
Under Voltage Load Shedding Program
3. Alberta Reliability Standard VAR-501-WECCAB-1 Power System Stabilizer
4. Alberta Reliability Standard VAR-002-AB-1.1b
Generator Operation for Maintaining Network
Voltages
The examples listed above have been consulted
on with industry and to date no market participant
has expressed concern that the applicability
subsections are unclear.
For greater certainty, with respect to proposed
New ISO Rules Section 502.3, the AESO will not
be monitoring the requirements of these rules for
a generating unit directly connected to the
Alberta interconnected electric system with a
maximum authorized real power rating equal to
AESO Replies to Stakeholder Comments: 2012-10-23
Page 4 of 10
or less than eighteen (18) MW, or an aggregated
generating unit directly connected to the Alberta
interconnected electric system with a maximum
authorized real power rating equal to or less than
sixty seven point five (67.5) MW, or the legal
owner of a transmission facility with a rated
voltage less than 100 kV.
Accordingly, the AESO has not amended final
proposed ISO Rules Section 502.3.
2. Requirements for two protection systems and subcomponents
will be clarified.
Subsection
7
AltaLink Management Ltd
3. Maximum protection relay operate times will be provided to
ensure transmission grade relays are utilized for new facilities.
Total clearing times will be addressed in the AESO’s upcoming
revision to the Planning Criteria.
Subsection
8
AltaLink Management Ltd
AltaLink supports this ISO requirement and has no
comment
9.
AltaLink supports with language suggestions.
AltaLink recommends that the wording in
subsection 8(1), 8(2), 8(3), 8(4) be adjusted to “…
the primary protection relay must be specified such
that the operate times…do not exceed…” to more
closely align with section 7.1 of ID 2012-004R.
No reply required.
9.
The AESO agrees with AltaLink’s language
suggestions. The intent of this requirement is to
ensure that the relay is capable of operating in
the specified time. As indicated in Section 7.2 of
draft ID# 2012-004R, the use of manufacture
specifications is acceptable. Relay test results
would also be acceptable.
Accordingly, the AESO has amended final
proposed ISO Rules Section 502.3.
4.
Event capture for new facilities and the need for GPS time
synchronization will be provided.
Subsection
14
AltaLink Management Ltd
10. AltaLink supports with language suggestions.
AltaLink recommends that this requirement be
amended to indicate “it applies only on the addition
of new power system elements and not
modifications or replacement of existing protection
systems.”
10. The AESO disagrees with AltaLink’s language
suggestions. As specified in proposed New ISO
Rules Section 502.3, a functional specification
issued on or after the effective date of proposed
New ISO Rules Section 502.3 must meet the
requirements of proposed New ISO Rules
Section 502.3 for all new facilities identified in a
project functional specification. If a market
participant identifies that for minimal additional
cost, the GPS signal could be added to other
existing lines to provide accurate event records
AESO Replies to Stakeholder Comments: 2012-10-23
Page 5 of 10
for those other lines, then the AESO may choose
to add this additional scope of work to the project
functional specification.
Accordingly, the AESO has not amended final
proposed ISO Rules Section 502.3.
11. AltaLink also recommends that the reference to a
global positioning system clock be removed from
14(3). It is recommended that the requirement be
amended to indicate accuracy to 1.0 ms of UTC.
The method of achieving the accuracy should be
left to the discretion of the legal owner of a
transmission facility.
5.
6.
Auto Reclosing – At 240kV and higher voltages, single pole
trip and reclose will become the standard practice for new
facilities. At 240kV and higher voltages, no three (3) pole trip
and reclose will be required. The success rate for reclosing
will be removed.
Protection System Communications – For now the 99.99%
availability will remain a requirement within proposed New ISO
Rules Section 502.3 for new facilities. This requirement will be
re-evaluated when the AESO develops its proposed
Communication Rules.
Subsections
16 and 17
AltaLink Management Ltd
12. AltaLink supports with language suggestions.
AltaLink requests further clarity on why single pole
trip and reclose will become the standard practice
for new facilities. Single pole trip and reclose
inherently adds cost and complexity, and likely
does not help the power system in most cases.
AltaLink recommends that the wording be adjusted
to make three pole trip and reclose the standard
practice for new facilities and define exceptions to
this in functional specifications.
Subsection
23
11. The AESO agrees with AltaLink’s language
suggestion, and accordingly, has amended final
proposed ISO Rules Section 502.3.
12. Over the past 2 years the AESO has been
reviewing the use of single pole trip and reclose
and is generally satisfied the benefit warrants the
cost for most applications. The AESO intends to
conclude its review and discuss these finding
with the transmission facility owners in the near
future. For now, the AESO will review and specify
reclosing type for all line 240kV and above on a
project basis.
Accordingly, the AESO has amended subsection
16 of final proposed ISO Rules Section 502.3.
AltaLink Management Ltd
AltaLink supports this ISO requirement and has no
comment
No reply required.
AESO Replies to Stakeholder Comments: 2012-10-23
Page 6 of 10
7.
Three Terminal Lines – Specific requirements will be provided
regarding the protection of new three (3) terminal lines.
Subsection
24
AltaLink Management Ltd
13. AltaLink supports with language suggestions.
AltaLink recommends that a statement be added to
subsection 24(1) requirement should be adjusted to
reflect, “No three (3) or more terminal lines shall be
allowed unless agreed to by the AESO and TFO’s.”
14. AltaLink recommends subsection 24(2) specify the
acceptable level of mis-coordination?
8.
9.
9.
500kV Protection System Setting Verification – Real time digital
simulation will be required for all new 500kV protection
systems.
Subsection
28
AltaLink Management Ltd
Transformer Protection – All new 25MVA and larger
transformers will require redundant transformer differential
protection.
Subsection
29
AltaLink Management Ltd
Bus Protection – New 144kV and lower voltage busses will
require redundant differential protection or studies to show
remote protections can provide adequate coverage.
Subsections
30 to 32
AltaLink Management Ltd
AltaLink supports this ISO requirement and has no
comment
AltaLink supports this ISO requirement and has no
comment
15. AltaLink supports with language suggestions.
AltaLink recommends further clarity be added in
section 9.2 of ID#2012-004R which states “Slower
clearing times than those specified in section 502.3
subsection 8 are acceptable.” Subsection 8 of
502.3 specifies protective relay operate times and
not fault clearing times.
13. The AESO disagrees with AltaLink’s language
suggestions. The AESO will address the
application of three (3) terminal lines in its
upcoming revision to the Planning Criteria or in
the upcoming proposed Substation Rules to be
developed. The scope of proposed ISO Rules
Section 502.3.remains unchanged and has not
been expanded as a result of this comment.
14. The AESO does not agree with AltaLink. Given
the complexity of three (3) terminal lines the
AESO intends to review the acceptable level of
mis-coordination on a project basis. Accordingly,
the AESO has not amended final proposed ISO
Rules Section 502.3.
No reply required.
No reply required.
15. The AESO agrees with AltaLink’s with regard to
allowing zone 2 clearing. The AESO has
amended draft ID# 2012-004R accordingly.
AESO Replies to Stakeholder Comments: 2012-10-23
Page 7 of 10
10.
Breaker Failure Protection – Based on extensive input from the
external technical workgroup clear requirements will be
provided that manage system reliability and where possible
allow for the lowest cost solutions.
Subsection
35
AltaLink Management Ltd
16. AltaLink supports with language suggestions.
AltaLink request further clarification if subsection
35(6) applies to contact based breaker failure
schemes such as cooling system trips for Static
Var Compensators where longer breaker failure
delay times are typically used.
16. The AESO agrees with AltaLink’s language
suggestions. The intention of this requirement is
to ensure high voltage faults are cleared quickly
such that system stability is maintained. Once a
primary protection system initiates a breaker
open signal, there should be no reason for the
breaker to take a longer time than specified.
However, for low level fault there is no stability
concern and longer times can be tolerated. .
Accordingly, the AESO has amended final
proposed ISO Rules Section 35 to clarify that this
requirement applies to solid single line to ground
or three phase faults.
17. AltaLink recommends that subsection 35(7) be
revised to state “For applications where free
standing current transformers are used with livetank breakers, it is acceptable to have a breaker
fail operation for faults located between the breaker
and the current transformer.”
11.
Generating Unit Protection – Minimum protection requirements
will be provided such that system reliability is maintained. Any
protection requirements beyond this will be left up to the
discretion of the owner of the unit.
Proposed
Change
Subsections
37 to 45
Reference to the Subsections in Proposed New ISO Rules
Section 502.3
17. The AESO agrees with AltaLink’s suggestion.
Accordingly the AESO has amended subsection
35(7) of final proposed ISO Rules Section 502.3.
AltaLink Management Ltd
AltaLink has no comment
No reply required.
Stakeholder Comments and/or Alternate Proposal
AESO Replies
AESO Replies to Stakeholder Comments: 2012-10-23
Page 8 of 10
(b) Subsections within Proposed New ISO Rules Section 502.3
AltaLink Management Ltd.
18. AltaLink supports with language suggestions.
In the AESO’s opinion, other than the key changes identified in (a) above, no other
substantive changes were made as the AESO redrafted and relocated
requirements from the AESO Protection Standard to proposed New ISO Rules
Section 502.3. As stakeholders review each subsection of New ISO Rules Section
502.3 please specifically comment on:
1) Are there any subsections where stakeholders feel that the language does not
clearly articulate the requirement either for the AESO or a market participant?
If yes, please indicate the subsection and suggest language that would more
clearly articulate the requirement.
AltaLink recommends that subsection 6(a) be
adjusted to reflect the wording in section 15.
AltaLink recommends that the existing subsection
be revised to state “successfully detect all phaseto-ground faults with ground impedance less than 5
Ohms, phase-to-phase-to-ground with ground
impedance less than 5 Ohms, phase-to-phase, and
three (3) phase faults on the protected equipment
within the zone of protection;”
18. The AESO agrees with AltaLink’s language
suggestion. Accordingly, the AESO has amended
subsection 6(a) of final proposed ISO Rules
Section 502.3.
19. AltaLink recommends that subsection 11 be made
generic to indicate alarming on loss of potential.
Other equipment such as miniature circuit breakers
may be used instead of fuses on voltage circuits.
AltaLink recommends that the existing statement
be revised to the following: “A voltage transformer
used for protective purposes, including
synchronism checking, must have a loss of
potential alarm.”
For Subsection 17(2):
19. The AESO agrees with AltaLink’s language
suggestion. Accordingly, the AESO has amended
subsection 11 of final proposed ISO Rules
Section 502.3.
20. AltaLink recommends further clarity be added to
subsection 17(2) to outline whether auto-reclosing
is permitted on hybrid lines (cables + overhead).
AltaLink also recommends that cables should be
made more generic by removing the word
“underground” as not all cables are installed
underground.
20. The AESO agrees with AltaLink’s language
suggestion. Accordingly, the AESO has amended
subsection 17(2) of final proposed ISO Rules
Section 502.3.
21. AltaLink recommends that the phrase “capacitor
bank can” in subsection 33(3) be replaced with the
word “element”.
21. The AESO agrees with AltaLink’s language
suggestion. Accordingly, the AESO has amended
subsection 33(3) of final proposed ISO Rules
Section 502.3.
AESO Replies to Stakeholder Comments: 2012-10-23
Page 9 of 10
AltaLink Management Ltd.
2) Are there any subsections where stakeholders feel that the requirement does
not appropriately address system reliability concerns? Please provide an
alternate proposal if possible.
AltaLink supports this ISO requirement and has no
comment
No reply required.
AESO Replies to Stakeholder Comments: 2012-10-23
Page 10 of 10