IEC TR 62511:2014
(Main)Guidelines for the design of interconnected power systems
Guidelines for the design of interconnected power systems
IEC TR 62511:2014(E) provides guidelines in planning and design of the interconnected power system (IPS) and consequently achieve the delivery of reliable supply service. The guidelines for the design of interconnected power systems within this document will enhance system reliability, mitigate many of the adverse impacts associated with the loss of a major portion of the system or unintentional separation of a major portion of the system, and will not be consequential because of normal design contingencies. In the context of this Technical Report, interconnected power system means an entity's (control area or a system operator) high-voltage transmission system that can adversely impact other connected systems due to faults and disturbances within its area. In the case of large areas, the system operator may define a subset of its area to keep the adverse impact contained within a smaller portion of its system. This Technical Report specifies the recommended techniques for securing an IPS to ensure a high level of reliability. Generally, interconnected power systems are synchronously connected or asynchronously connected through DC interconnections. This document aims to ensure that the interconnections are designed and operated consistently on both ends. The recommendations include design and operation requirements to withstand the primary contingencies specified in this document.
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Standards Content (Sample)
IEC TR 62511 ®
Edition 1.0 2014-09
TECHNICAL
REPORT
Guidelines for the design of interconnected power systems
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IEC TR 62511 ®
Edition 1.0 2014-09
TECHNICAL
REPORT
Guidelines for the design of interconnected power systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
U
ICS 29.240.99 ISBN 978-2-8322-1865-5
– 2 – IEC TR 62511:2014 © IEC 2014
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 General principles . 14
4.1 General requirements . 14
4.2 System analysis and modeling data exchange requirements . 15
5 Resource adequacy . 15
6 Modeling and assessments . 16
6.1 General . 16
6.2 Stability assessment . 16
6.3 Steady state assessment . 17
6.4 Real time system conditions . 17
6.5 Normal transfers . 17
6.6 Emergency transfers . 18
6.7 Post contingency operation . 18
6.8 Operation under high risk conditions . 18
6.9 Extreme contingency assessment . 19
6.10 Extreme system conditions assessment . 19
6.11 Fault current assessment . 20
7 IPS design guidelines . 20
7.1 General . 20
7.2 Redundancy in transmission system design . 20
7.3 Protection and control system design . 20
7.4 Considerations for issues affecting protection systems reliability and
dependability . 22
7.5 Considerations for issues affecting security . 22
7.6 Considerations for issues affecting dependability and security . 22
7.7 Protection operating time . 23
7.8 Protection system testing . 23
7.9 Analysis of protection performance . 23
7.10 Considerations for current and voltage transformers . 23
7.10.1 AC current transformers . 23
7.10.2 AC voltage transformers (VT), capacitance coupler voltage transformer
(CCVT), and fiber optic voltage transducers . 24
7.11 Logic systems . 24
7.12 Microprocessor-based equipment and software . 24
7.13 Batteries and direct current (DC) auxiliary supply . 24
7.14 Station service AC supply . 25
7.15 AC circuit breakers . 25
7.16 Teleprotection (communication for protective functions) . 25
7.17 Control cables and wiring and ancillary control devices . 26
7.18 Environment . 26
7.19 Grounding . 26
7.20 Specific application considerations . 26
7.20.1 AC transmission line protection . 26
7.20.2 Transmission station protection . 27
7.20.3 AC breaker failure protection . 27
7.20.4 Generating station protection . 27
7.20.5 HVDC system protection . 28
7.20.6 AC capacitor bank protection . 28
7.20.7 Static VAR compensator (SVC) protection . 29
7.21 Reporting of protection systems . 29
Bibliography . 30
– 4 – IEC TR 62511:2014 © IEC 2014
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GUIDELINES FOR THE DESIGN OF
INTERCONNECTED POWER SYSTEMS
FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
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example "state of the art".
IEC/TR 62511, which is a technical report, has been prepared by IEC technical committee 8:
Systems aspects for electrical energy supply.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
8/1346/DTR 8/1364/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
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related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
– 6 – IEC TR 62511:2014 © IEC 2014
GUIDELINES FOR THE DESIGN OF
INTERCONNECTED POWER SYSTEMS
1 Scope
The primary objective of this Technical Report is to provide guidelines in planning and design
of the interconnected power system (IPS) and consequently achieve the delivery of reliable
supply service. The guidelines for the design of interconnected power systems within this
document will enhance system reliability, mitigate many of the adverse impacts associated
with the loss of a major portion of the system or unintentional separation of a major portion of
the system, and will not be consequential because of normal design contingencies.
In the context of this Technical Report, interconnected power system means an entity’s
(control area or a system operator) high-voltage transmission system that can adversely
impact other connected systems due to faults and disturbances within its area. In the case of
large areas, the system operator may define a subset of its area to keep the adverse impact
contained within a smaller portion of its system.
This Technical Report specifies the recommended techniques for securing an IPS to ensure a
high level of reliability. Generally, interconnected power systems are synchronously
connected or asynchronously connected through DC interconnections. This document aims to
ensure that the interconnections are designed and operated consistently on both ends. The
recommendations include design and operation requirements to withstand the primary
contingencies specified in this document.
It is recommended that each entity ensures that its portion of the high voltage IPS is designed
and operated in unison with these guidelines. This precaution is recommended, otherwise
additional system interconnections can cause significant adverse impacts on reliability of the
connected entities. Each entity is also encouraged to make use of committees, task forces,
working groups, interregional studies and other methods in order to ensure their IPS is
constantly updated/enhanced and maintained, in such a way that it is in agreement with these
guidelines.
NOTE The application of this guide is for high voltage transmission systems (generally over 50 kV). However,
mitigation measures for certain system conditions, such as under frequency load shedding (UFLSh), are frequently
required for low voltage distribution systems; hence, for the purpose of this transmission guide, interconnected
control areas and/or system operators can establish the voltage level, as required. In addition, the design
guidelines in this document are intended only for those elements of the IPS (not the entire high voltage
transmission system) that can adversely impact other connected system(s) due to faults and disturbances within an
area or a predefined subset of a large area. This document also provides guidance to determine such elements of
the IPS.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
None.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
adequacy
ability of an electric power system to supply the aggregate electric power and energy required
by the customers, under steady-state conditions, with system component ratings not
exceeded, bus voltages and system frequency maintained within tolerances, taking into
account planned and unplanned system component outages
Note 1 to entry: The ability may be measured by one or several appropriate indices.
[SOURCE: IEC 60050-191:1990, 191-21-01]
3.2
continuous capacity
rated continuous load-carrying ability, expressed in megawatts (MW) or megavolt-amperes
(MVA) of generation, transmission, or other electrical equipment
3.3
maximum capacity of a unit
the maximum power that could be generated by a unit, under continuous operation with all of
its components in working order
Note 1 to entry: This power may be gross or net.
[SOURCE: IEC 60050-602:1983, 602-03-08]
3.4
contingency
event, usually involving the loss of one or more elements, which affects the IPS at least
momentarily
3.5
control area
electric system or systems, bounded by interconnection metering and telemetry, capable of
controlling generation to maintain its net interchange schedule with other control areas and
contributing to frequency regulation of interconnections
3.6
demand
the magnitude of an electricity supply, expressed in kilowatts or kilovoltamperes
[SOURCE: IEC 60050-691:1973, 691-02-02]
3.7
element of power system
any electric device with terminals that may be connected to other electric devices
EXAMPLE A generator, transformer, circuit breaker, or bus section.
3.8
emergency
any abnormal system condition that requires automatic or manual action to prevent or limit the
loss of transmission facilities, or generation supply that could adversely affect the reliability of
the electric system
Note 1 to entry: An emergency is considered to exist in a region of an entity where a firm load has to be shed.
– 8 – IEC TR 62511:2014 © IEC 2014
3.8.1
emergency limits
limits which can be utilized for the time required to take corrective action
Note 1 to entry: The limiting condition for voltages should recognize that voltages should not drop below that
required for suitable system stability performance, and should not adversely affect the operation of the IPS.
Note 2 to entry: The limiting condition for equipment loadings should be such that cascading outages will not
occur as a result of the operation of protective devices upon the failure of facilities. (Various definitions of
equipment ratings are found in this guide.)
3.8.2
applicable emergency limits
limits which depend on the duration of the occurrence and on the policy of the given entity
regarding loss of life to equipment, voltage limitations, etc.
3.9
fault
an unplanned occurrence or defect in an item which may result in one or more failures of the
item itself or of other associated equipment
Note 1 to entry: A fault is often the result of a failure of the item itself, but may exist without prior failure.
[SOURCE: IEC 60050-604:1987, 604-02-01, modified – addition of Note 1 to entry]
3.9.1
delayed fault clearing
fault clearing which is consistent with the correct operation of a breaker failure protection
group and its associated breakers, or of a backup protection group with an intentional time
delay
3.9.2
normal fault clearing
fault clearing which is consistent with the correct operation of the protection system and with
the correct operation of all circuit breakers or other automatic switching devices intended to
operate in conjunction with that protection system
3.10
generation (of electricity)
a process of producing electrical energy from other forms of energy
Note 1 to entry: The amount of electric energy produced, usually expressed in kilowatt-hours (kWh) or megawatt
hours (MWh).
[SOURCE: IEC 60050-601:1985, 601-01-06 modified – modified definition and addition of
Note 1 to entry]
3.11
high-voltage d.c. link
HVDC link
an installation for transmitting large quantities of electricity at high-voltage d.c., including the
converter substations
[SOURCE: IEC 60050-601:1985, 601-04-01]
3.12
interconnected power system
IPS
interconnected electrical power system within a wide area, comprised of system elements
assigned to different local areas within the same operating authority or a different operating
authority (e.g. ISOs) on which faults or disturbances can have a significant adverse impact
outside of the local area
3.13
interconnection
interconnexion
single or multiple transmission links between transmission systems enabling electric power
and energy to be exchanged between these networks by means of electric circuits and/or
transformers
Note 1 to entry: In the context of this document interconnection refers to facilities that connect two or more IPSs
or control areas. Additionally, interconnection also refers to the facilities that connect a non-utility generator to a
control area or IPS.
[SOURCE: IEC 60050-601:1985, 601-01-11, modified – "electricity" replaced by "electric
power and energy", "systems" replaced by "networks", "electric" added to "circuits" and
addition of Note 1 to entry]
3.14
load
device intended to absorb power supplied by another device or an electric power system
[SOURCE: IEC 6005-151:2001, 151-15-15]
3.14.1
firm load
load that is not an interruptible load – load that is served on a guaranteed basis, 100 % of the
time
3.14.2
interruptible load
load of particular consumers which, according to contract, can be disconnected by the supply
undertaking for a limited period of time
[SOURCE: IEC 60050-603:1986, 603-04-41]
3.15
load relief
reduction in amount of customer load caused by deliberate voltage reduction in response to
an abnormal operating condition of the electric power system and/or load shedding
3.16
load shedding
the process of deliberately disconnecting preselected loads from a power system in response
to an abnormal condition in order to maintain the integrity of the remainder of the system
[SOURCE: IEC 60050-603:1986, 603-04-32]
3.17
load current
I
load
highest continuous ampere on line or other series elements rating, that most closely
approximates a 4-hour rating of the line
– 10 – IEC TR 62511:2014 © IEC 2014
3.18
native
belonging to the person, place or thing in question
3.19
operating limit
the maximum value of the most critical system operation parameter(s) which meets: (a) pre-
contingency criteria as determined by equipment loading capability and acceptable voltage
conditions, (b) stability criteria, and (c) post-contingency loading and voltage criteria
3.20
outage
unavailability
the state of an item of being unable to perform its required function
[SOURCE: IEC 60050-603:1986, 603-05-05]
3.20.1
forced outage
unplanned outage whose onset, automatic or manual, cannot be deferred
[SOURCE: IEC 60050-191:1990, 191-24-03]
3.20.2
maintenance outage
the removal of equipment from service to perform work on specific elements that can be
deferred
3.20.3
planned outage
outage scheduled in advance, for maintenance or other purposes
[SOURCE: IEC 60050-191:1990, 191-24-01]
3.21
pole (of an equipment)
in certain types of equipment such as switchgear, the part corresponding to one of the phases
in a.c. or to one of the polarities in d.c.
Note 1 to entry: According to the number of poles within the equipment, it is called: single-pole equipment, two-
pole equipment, etc.
[SOURCE: IEC 60050-601:1985, 601-03-11]
3.22
HVDC terminal
rectifier and an inverter, with associated filter banks and control equipment, tied together by a
transmission line or bus
3.23
protection
provisions for detecting faults or other abnormal conditions in a power system, for enabling
fault clearance, for terminating abnormal conditions, and for initiating signals or indications
Note 1 to entry: The term “protection” is a generic term for protection equipment or protection systems.
Note 2 to entry: The term “protection” may be used to describe the protection of a complete power system or the
protection of individual plant items in a power system e.g. transformer protection, line protection, generator
protection.
Note 3 to entry: Protection does not include items of power system plant provided, for example, to limit over
voltages on the power system. However, it includes items provided to control the power system voltage or
frequency deviations such as automatic reactor switching, load-shedding, etc.
[SOURCE: IEC 60050-448:1995, 448-11-01]
3.23.1
protection system
protection group
an arrangement of one or more protection equipments, and other devices intended to perform
one or more specified protection functions
Note 1 to entry: A protection system includes one or more protection equipments, instrument transformer(s),
wiring, tripping circuit(s), auxiliary supply(s) and, where provided, communication system(s). Depending upon the
principle(s) of the protection system, it may include one end or all ends of the protected section and, possibly,
automatic reclosing equipment.
Note 2 to entry: The circuit-breaker(s) are excluded.
[SOURCE: IEC 60050-448:1995, 448-11-04, modified – addition of "protection group"]
3.24
element basis
one or more protection groups, including all equipment such as instrument transformers,
station wiring, circuit breakers and associated trip/close modules, and communication
facilities
Note 1 to entry: It is installed at all terminals of a power system element to provide the complete protection of that
element.
3.25
protective relay
protection relay
measuring relay which, either solely or in combination with other relays, is a constituent of a
protection equipment
[SOURCE: IEC 60050-448:1995, 448-11-02]
3.26
relay
electrical device designed to produce sudden predetermined changes in one or more electric
output circuits, when certain conditions are fulfilled in the electric input circuits controlling the
device
[SOURCE: IEC 60050-151:2001, 151-13-31]
3.27
reliability
the ability of an item to perform a required function under given conditions for a given time
interval
Note 1 to entry: It is generally assumed that the item is in a state to perform this required function at the
beginning of the time interval.
Note 2 to entry: Electric system reliability can be quantified using appropriate measures by considering two basic
and functional aspects of the electric system — adequacy and security.
Note 3 to entry: Probability that an electric power system can perform a required function under given conditions
for a given time interval.
[SOURCE: IEC 60050-191:1990, 191-02-06, modified – removal of original Note 2 and
addition of new Notes 2 and 3 to entry]
– 12 – IEC TR 62511:2014 © IEC 2014
3.28
spinning reserve
generating capacity, kept in reserve to compensate for all possible deviations in the power
balance that may occur between normal conditions and those which actually occur, and thus
to ensure a reliable and economic electricity supply
3.29
resource
any physically or conceptually identifiable entity whose use and state at any time can be
unambiguously determined
Note 1 to entry: For this document, refers to the total contributions provided by supply-side and demand-side
facilities and/or actions. Supply-side facilities include utility and non-utility generation and purchases from
neighboring systems. Demand-side facilities include measures for reducing load, such as conservation, demand
management, and interruptible load.
[SOURCE: IEC 60050-715:1996, 715-02-01, modified – addition of Note 1 to entry]
3.30
security
ability of an electric power system to operate in such a way that credible events do not give
rise to loss of load, stresses of system components beyond their ratings, bus voltages or
system frequency outside tolerances, instability, voltage collapse, or cascading
Note 1 to entry: This ability may be measured by one or several appropriate indices.
Note 2 to entry: This concept is normally applied to bulk power systems.
Note 3 to entry: In North America, this concept is usually defined with reference to instability, voltage collapse
and cascading only.
[SOURCE: IEC 60050-191:1990, 191-21-03]
3.31
short circuit
accidental or intentional conductive path between two or more conductive parts, whether
made accidently or intentionally, forcing the electric potential differences between these
conductive parts to be equal to or close to zero (relatively low impedance)
Note 1 to entry: The term fault or short-circuit fault used in this document refers to a short circuit.
3.32
significant adverse impact
instability, unacceptable system dynamic response, unacceptable equipment tripping;
voltage/frequency levels in violation of applicable emergency limits, and/or loadings on
transmission facilities in violation of applicable emergency limits
Note 1 to entry: With due regard for the maximum operating capability of the affected systems, one or more of the
following conditions arising from faults or disturbances shall be deemed as having significant adverse impact:
a) instability
– any instability that cannot be demonstrably contained to a well-defined local area
– any loss of synchronism of generators that cannot be demonstrably contained to a well-defined local area
b) unacceptable system dynamic response
– an oscillatory response to a contingency that is not demonstrated to be clearly positively damped within
30 s of the initiating event
c) unacceptable equipment tripping
– tripping of an un-faulted IPS element (element that has already been classified as IPS) under planned
system configuration due to operation of a protection system in response to a stable power swing
– special protection system in response to a condition for which its operation is not required
3.33
special protection system
SPS
protection system designed to detect abnormal system conditions, and take corrective action
other than the isolation of faulted elements
Note 1 to entry: Such action may include changes in load, generation, or system configuration to maintain
system stability, acceptable voltages or power flows. Conventionally switched, locally controlled shunt devices are
not SPSs, while Generation Rejection Protection Scheme for system stability is an SPS. As an example, automatic
under frequency load shedding to stabilize the system frequency in an area during an event leading to declining
frequency is not considered an SPS.
3.34
stability
ability of an electric system to maintain a state of equilibrium during normal and abnormal
conditions or disturbances
Note 1 to entry: Power system stability can be classified as voltage, rotor angle and frequency stability.
3.35
substation (of a power system)
a part of an electrical system, confined to a given area, mainly including ends of transmission
or distribution lines, electrical switchgear and control gear, buildings and transformers
Note 1 to entry: A substation generally includes safety or control devices (for example protection).
Note 2 to entry: The substation can be qualified according to the designation of the system of which it forms a
part. Examples: switching, transmission, substation (transmission system), distribution substation, 400 kV or 20 kV
substations.
[SOURCE: IEC 60050-601:1985, 601-03-02]
3.36
transfer capability
operating limit relating to the permissible power transfer between specified areas of the
transmission system
Note 1 to entry: The units of transfer capability are in terms of electric power, generally expressed in megawatts
(MW). In this context, "area" may be an individual electric system, power pool, control area, sub-region, or region,
or a portion of any of these. Transfer capability is directional in nature. That is, the transfer capability from "Area A"
to "Area B" is not generally equal to the transfer capability from "Area B" to "Area A".
3.36.1
emergency transfer capability
amount of power transfer allowed between entities or within an entity when operating
achieving emergency criteria contingencies
3.37
transmission system
TS
the whole of the means of transmission between two points, comprising the transmission
medium, terminal equipment, any necessary intermediate equipment and any equipment
provided for such ancillary purposes as power feeding, supervision and testing
[SOURCE: IEC 60050-704:1993, 704-04-10, modified – definition 1 removed]
3.37.1
primary transmission system
PTS
transmission portion of the IPS of an entity, that generally consisting of EHV/HV transmission
system
– 14 – IEC TR 62511:2014 © IEC 2014
Note 1 to entry: For this document, it can be part of intra-entity and/or inter-entity system connections. Generally
connected through auto transformation to connect generation and large load connections. Typical examples are:
transmission grid/inter-entity connections (generally > 100 kV), generation (generally > 100 MW), and load
consumers (>100 MW).
3.37.2
secondary transmission system
STS
transmission portion of the IPS of an entity that generally consists of HV and MV transmission
system
Note 1 to entry: For this document, it can be part of intra-entity and/or inter-entity system connections. Generally
connects to primary transmission systems, sub-transmission, generation, and large & medium load connections.
Typical examples are: secondary transmission (50 kV< STS < 200 kV), generation (generally 5 MW to 100 MW)
and load consumers (20 MW to 100 MW).
3.38
voltage reduction
a relatively small decrease in the system operating voltage used as a means to reduce the
demand by lowering the customer’s voltage
[SOURCE: IEC 60050-604:1987, 604-01-21, modified – additional text "used as … voltage"
added]
4 General principles
4.1 General requirements
The application of this Technical Report is for high voltage transmission systems (generally
over 50 kV). However, mitigation measures for certain system conditions, such as under
frequency load shedding (UFLSh), are frequently required for low voltage distribution
systems; hence, for the purpose of this transmission guide, interconnected control areas
and/or system operators should establish the voltage level, if required. In addition, local
conditions may require criteria which are more stringent than those set out herein. Hence,
these guidelines should be treated as minimum requirements. Any constraints imposed by the
local conditions or more stringent criteria should be adhered to. It is also recognized that
these guidelines are not necessarily applicable to those elements of the high voltage
transmission system on which disturbances and/or contingencies will not adversely impact the
safe, secure and reliable operation of the interconnected power system (IPS), or to those
elements which happen to be contained in the portions of a local system where instability
and/or overloads will not jeopardize the reliability of the remaining interconnected power
system.
The guidelines in this document should be used in the assessment and in the reliability testing
of an entity’s high voltage transmission system to determine the elements of IPS for enhanced
design.
Design studies should assume that power flow conditions utilizing load transfers and
generation conditions will stress the system. For example, transfer capability studies should
be based on the load and generation conditions which are expected to exist for the period
under study followed with sensitivity studies for light load or higher load during extreme
weather conditions. All reclosing facilities should be assumed in service, unless it is known
that such facilities will be rendered inoperative.
Special protection systems (SPS) may be employed, in the interest of maintaining system
security, for facilities which are not available to meet demand. An SPS may also be applied
for economic reasons or to preserve system integrity in the event of severe facility outages
and extreme contingencies. However, a special protection system (SPS) should be used with
caution when employed. It is recommended that SPS be installed consistently with good
system design and operating policy. Depending upon the consequences of SPS failure, full
redundancy should be considered in its implementation. Generally speaking, SPS may be
used to provide protection from infrequent contingencies or from temporary conditions that
may exist such as: project delays, unusual combinations of system demand, and equipment
outages or availability. The decision to employ an SPS should take into account the
complexity of the scheme and the consequences as well as the benefits of correct operation
or the risks associated with incorrect operation.
It is not intended to establish operating guidelines in this document. However, it is extremely
important to mention that for effective planning and design, coordination among and within
interconnected entities operating IPSs is essential to the reliability of interconnected
operations. For example, timely information concerning system conditions should be
transmitted by the native entities to any other collaborating entities working synchronously or
asynchronously through HVDC links with one another.
Where inter-entity reliability is concerned, each native entity (facility owner) should identify
the ratings of its equipment; the lowest ratings shall be considered in determining the
operating limits of the interconnection facilities. Once the operating limits are determined, the
interconnection facilities shall be designed to withstand the contingencies stated in 6.2 and
6.3 without causing a significant adverse impact on the other interconnected entities.
4.2 System analysis and modeling data exchange requirements
For reliability purposes, collaborating entities should arrange to share and coordinate forecast
system information, along with real time information, in order to enhance the analysis and
modeling of security application software on energy management systems that pertain to
interconnected power systems.
It is also strongly recommended that collaborating entities acquire accurate and up-to-date
system modeling information and disclose the data required to analyze and model their IPSs.
Using the shared data, component facilities can be properly modeled for assessments. Data
sharing is also recommended for fault level analysis, as well as for use in interconnected
operations and planning studies.
It is recommended that data submitted for analysis pertaining to physical or control
characteristics of equipment should be verified through the appropriate methods such as
testing and disturbance analysis. System analysis and modeling data should be reviewed at
least annually and verified on a periodic basis for consistency. Additionally, generation
equipment, and its component controllers, should be tested to verify their conditions.
Entities should install dynamic recording devices and should be able to provide the recorded
data necessary to enhance the analysis of system wide disturbances and validate system
simulation models.
These recording devices should be time synchronized and should have sufficient data storage
to permit several minutes of data to be collected. Information provided by these recordings
should be used in tandem with shorter time scale readings from fault recorders, and with
sequence of events recorders (SER) when appropriate.
NOTE It is the responsibility of the given entity to protect its proprietary information and to ensure it is used only
for the purposes of efficient and reliable system operation and design. Also, should the entity in question report to
any other governing bodies, or collaborate with any other entities, it is responsibility of the native entity to ensure
that the sharing of such information does not violate any anti-trust laws.
5 Resource adequacy
An entity’s risk of disconnecting a firm load due to resource deficiencies should be, on
average, no more than a pre-determined time interval (for example, once every ten years).
Compliance with this criterion should be evaluated probabilistically such that the loss of load
expectation (LOLE) of disconnecting a firm load is respected. This evaluation should make
due allowance for demand uncertainty, scheduled outages and deratings, forced outages and
– 16 – IEC TR 62511:2014 © IEC 2014
deratings, assistance over interconnections with collaborating entities, transmission transfer
capabilities and capacity, and/or load reduction from available operating procedures.
Each entity should have procedures in place to schedule outages and deratings of resources
in such a manner that the available resources will be adequate to meet the entity’s forecasted
load and spinning reserve requirements.
For consistent reporting of resource sufficiency, it is suggested that a measure of the net
capability of generating units and loads be utilized as a resource of each entity on a regular
basis.
6 Modeling and assessments
6.1 General
Each entity should consider appropriate equipment characteristics, system modeling data,
and existing and future interchange schedules in accordance with its respective
interconnection for steady-state and dynamic modeling for simulation and assessments. It
should also include adequate considerations of interconnected renewable and distributed
resources.
Each entity's portion of the high voltage power system should be designed with sufficient
transmission capability to serve forecasted loads under the conditions noted in 6.2 and 6.3.
These recommended criteria should also hold after any critical generator and/or significant
load, transmission circuit, transformer, series or shunt compensating device or HVDC pole
has already been lost, assum
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