SIST EN 60834-1:2001
(Main)Teleprotection equipment of power systems - Performance and testing -- Part 1: Command systems
Teleprotection equipment of power systems - Performance and testing -- Part 1: Command systems
Applies to narrow-band (max. 4 kHz) teleprotection equipment, both single-signal and multi-signal. Also applies to voice-frequency equipment used with various telecommunications systems, such as power line carrier (PLC), radio links, rented circuits and leased or owned cables. Establishes performance requirements and test methods for testing channels used for transmitting command information required by protective devices in power systems, and gives the associated terminology.
Schutzsignal-Übertragungseinrichtungen für Energieversorgungsnetze - Leistungsmerkmale und Prüfungen -- Teil 1: Systeme mit Übertragung von Befehlen
Matériels de téléprotection des réseaux d'énergie électrique - Performances et essais -- Partie 1: Systèmes de commande
S'applique aux matériels de téléprotection à bande étroite (max. 4 kHz) à signal unique ou multiple. S'applique également aux matériels à fréquences vocales utilisés avec divers systèmes de télécommunications, tels que courant porteur sur ligne d'énergie, liaisons radioélectriques, circuits loués et câbles concédés aux privés. Etablit les prescriptions pour les performances et les méthodes d'essai des voies utilisées par les signaux de transmission d'information de commande nécessaires aux dispositifs de protection des réseaux d'énergie électrique et donne la terminologie s'y rapportant.
Teleprotection eqiupment of power systems - Performance and testing - Part 1: Command systems (IEC 60834-1:1999)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2001
1DGRPHãþD
SIST HD 543.1 S1:1997
Teleprotection eqiupment of power systems - Performance and testing - Part 1:
Command systems (IEC 60834-1:1999)
Teleprotection equipment of power systems - Performance and testing -- Part 1:
Command systems
Schutzsignal-Übertragungseinrichtungen für Energieversorgungsnetze -
Leistungsmerkmale und Prüfungen -- Teil 1: Systeme mit Übertragung von Befehlen
Matériels de téléprotection des réseaux d'énergie électrique - Performances et essais --
Partie 1: Systèmes de commande
Ta slovenski standard je istoveten z: EN 60834-1:1999
ICS:
29.240.20 Daljnovodi Power transmission and
distribution lines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
NORME CEI
INTERNATIONALE IEC
60834-1
INTERNATIONAL
Deuxième édition
STANDARD
Second edition
1999-10
Matériels de téléprotection des
réseaux d'énergie électrique –
Performances et essais –
Partie 1:
Systèmes de commande
Teleprotection equipment of power systems –
Performance and testing –
Part 1:
Command systems
IEC 1999 Droits de reproduction réservés Copyright - all rights reserved
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microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
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XA
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Pour prix, voir catalogue en vigueur
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60834-1 IEC:1999 – 3 –
CONTENTS
Page
FOREWORD . 7
Clause
1 General. 9
1.1 Scope . 9
1.2 Normative references. 9
1.3 Service conditions. 11
1.4 Telecommunication system used. 13
1.5 Definitions. 15
2 Characteristics of command type teleprotection systems . 23
2.1 Types of teleprotection command schemes . 23
2.2 Overall operating time of teleprotection systems
(telecommunication circuit included). 23
2.3 Transmission times (telecommunication circuit excluded) . 23
2.4 Security . 25
2.5 Dependability . 27
2.6 Nominal frequency band or bit rate . 29
2.7 Nominal impedance. 29
2.8 Guard signals/Command signals . 29
2.9 Levels of guard signals (analogue systems only) . 29
2.10 Levels of command signals (analogue systems only) . 29
3 Requirements for command type teleprotection systems. 31
3.1 General equipment interface requirements . 31
3.2 Specific power supply requirements. 37
3.3 Teleprotection system performance requirements. 39
4 Methods for performance testing . 47
4.1 General equipment interface tests . 47
4.2 Specific power supply tests . 49
4.3 Teleprotection system performance tests . 51
Annex A (informative) Teleprotection system performance tests. 99
Annex B (informative) Binary symmetric channel (BSC) model . 107
Annex C (informative) Example of a security analysis for a simple protocol . 109
Figure 1 – Voice frequency configuration . 69
Figure 2 – Power line carrier frequency configuration . 69
Figure 3 – Directly connected digital teleprotection (example) . 69
Figure 4 – Digital teleprotection connected via a multiplexed communication system . 69
Figure 5 – Fundamental terms on protection and teleprotection. 71
60834-1 IEC:1999 – 5 –
Page
Figure 6 – Typical operating times for protection systems incorporating teleprotection. 73
Figure 7 – Test circuit for testing power supply interruptions . 75
Figure 8 – Test circuit for LF disturbance emission measurement. 75
Figure 9 – Examples of the probability of missing command versus signal-to-noise ratio . 77
Figure 10 – Test set-up for dependability measurement (analogue teleprotection) . 79
Figure 11 – Test set-up for dependability measurement (digital teleprotection) . 79
Figure 12 – Test set-up for security measurement (analogue teleprotection). 81
Figure 13 – Test set-up for security measurement (digital teleprotection) . 81
Figure 14 – Examples of probability of unwanted commands versus signal-to-noise ratio
for 200 Bd channel . . 83
Figure 15 – Test set-up for measuring transmission time. 85
Figure 16 – Test set-up for measuring interference by discrete frequencies. 85
Figure 17 – Test set-up for measuring interference by frequency deviation . 87
Figure 18 – Frequency deviation versus time for test set-up in figure 17 . 87
Figure 19 – Test set-up for recovery time measurement for digital teleprotection . 89
Figure 20 – Test set-up for recovery time measurement for analogue teleprotection . 89
Figure 21 – Performance guidance figures for various teleprotection schemes . 91
Figure 22 – Example of dependability curves for digital teleprotection. 93
Figure 23 – Example of security curve for digital teleprotection. 95
Figure 24 – Test set-up for measuring jitter at the output of a digital
teleprotection transmitter .97
Figure 25 – Jitter mask for testing jitter at the input of a digital teleprotection receiver . 97
Figure A.1 – Graph showing the uncertainty of probability for a confidence level
of 95 % for various values of E and N . 103
Figure A.2 – Examples of probability of unwanted commands versus signal-to-noise ratio
for a 200 Bd channel. 105
60834-1 IEC:1999 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
TELEPROTECTION EQUIPMENT OF POWER SYSTEMS –
PERFORMANCE AND TESTING –
Part 1: Command systems
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60834-1 has been prepared by IEC technical committee 57: Power
system control and associated communications.
This second edition cancels and replaces the first edition published in 1988.
The text of this standard is based on the following documents:
FDIS Report on voting
57/406/FDIS 57/425/RVD
Full information on the voting for the approval of this standard 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 3.
Annexes A, B and C are for information only.
The committee has decided that this publication remains valid until 2004. At this date, in
accordance with the committee’s decision, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
60834-1 IEC:1999 – 9 –
TELEPROTECTION EQUIPMENT OF POWER SYSTEMS –
PERFORMANCE AND TESTING –
Part 1: Command systems
1 General
1.1 Scope
This part of IEC 60834 applies to teleprotection command systems used to convey command
information, generally in conjunction with protection equipment. It aims at establishing
performance requirements and recommended testing methods for command type teleprotection
equipment. The information conveyed by the teleprotection equipment can be in analogue or
digital form.
The command type teleprotection equipment referred to in this standard can be power line
carrier equipment or voice frequency equipment which is used in connection with various
telecommunication systems, such as power line carrier (PLC), radio links, optical fibre, rented
circuits, leased or privately owned cables. In addition the command type teleprotection can be
digital equipment which is used with a digital telecommunication system or media such as
optical fibres, radio links, leased or privately owned digital links.
The command type teleprotection equipment may be separate or provided as an integral part of
the protection equipment.
In addition to teleprotection equipment performance tests, tests have to be carried out on the
power supply of the teleprotection equipment. All the tests should be regarded as type tests.
NOTE – According to the International Electrotechnical Vocabulary (IEV), a type test is defined as a test of one or
more devices made to a certain design to show that the design meets certain specifications.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60834. For dated references, subsequent amendments
to, or revisions of, any of these publications do not apply. However, parties to agreements
based on this part of IEC 60834 are encouraged to investigate the possibility of applying the
most recent editions of the normative documents indicated below. For undated references, the
latest edition of the normative document referred to applies. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050(151):1978, International Electrotechnical Vocabulary – Chapter 151: Electrical and
magnetic devices
IEC 60050(448):1995, International Electrotechnical Vocabulary – Chapter 448: Power system
protection
60834-1 IEC:1999 – 11 –
IEC 60060-1:1989, High voltage test techniques – Part 1: General definitions and test
requirements
IEC 60870-2-1:1995, Telecontrol equipment and systems – Part 2: Operating conditions –
Section 1: Power supply and electromagnetic compatibility
IEC 60870-2-2:1996, Telecontrol equipment and systems – Part 2: Operating conditions –
Section 2: Environmental conditions (climatic, mechanical and other non-electrical influences)
IEC 61000-4-1:1992, Electromagnetic compatibility (EMC) – Part 4: Testing and measurement
techniques – Section 1: Overview of immunity tests. Basic EMC publication
ITU-T G.823:1993, The control of jitter and wander within digital networks which are based on
the 2048 kbit/s hierarchy
CISPR 22:1997, Information technology equipment – Radio disturbance characteristics – Limits
and methods of measurement
1.3 Service conditions
With reference to IEC 60870-2-1 and IEC 60870-2-2, the following specifications shall apply.
Special requirements or detailed specifications for other environmental conditions (climatic,
mechanical or other non-electrical influences), not covered in the following but considered
relevant for the proper operation and life of the equipment, shall be agreed between user and
manufacturer, preferably referring to specific classes mentioned in the IEC references above.
Class C2 is the preferred specification for severe environments (temperature range: –25 °C to
+55 °C) except that high relative humidity shall be specified as 95 %.
1.3.1 Ambient conditions
The stated performance requirements shall be satisfied for the conditions corresponding to
location class B3 (enclosed locations – air temperature controlled), the main characteristic
being the following:
• temperature range +5 °C to +40 °C
1.3.2 Supply voltage with battery operation
The nominal d.c. voltage is typically 250 V, 220 V, 125 V, 110 V, 60 V, 48 V or 24 V.
The stated performance requirements shall be satisfied for the following voltage tolerance
class:
• voltage tolerance DC3 –20 % to +15 %
60834-1 IEC:1999 – 13 –
1.3.3 Supply voltage with a.c. mains operation
The nominal a.c. voltage shall be chosen from the preferred values of 230 V r.m.s. or 110 V r.m.s
single-phase 50 Hz or 60 Hz.
The stated performance requirements shall be satisfied for the following tolerance classes:
• voltage tolerance AC2 +10 % to –15 %
• frequency tolerance F3 ±5 %
• harmonic content H1 <5 %
1.3.4 Storage conditions
During storage or shipment, the equipment shall not suffer any damage when the ambient
conditions correspond to location class C3 for storage and to class C2 for transportation, the
main characteristic being:
• temperature range –40 °C to +70 °C
1.4 Telecommunication system used
The telecommunication system can be
a) cable links for voice frequency transmission;
b) carrier frequency links for cables and overhead lines;
c) carrier frequency links on aerial cables on power lines;
d) power line carrier (PLC) links;
e) point-to-point radio links (microwave);
f) leased circuits;
g) optical fibres.
The telecommunication systems should be chosen with care since they can be influenced by
noise, change of parameters and other types of interference which may cause unwanted
operation or the non-operation of the teleprotection equipment.
Figure 1 shows teleprotection equipment working in an audio-frequency configuration
(e.g. using part of a 4 kHz band). The signals are conveyed from the transmitter to the receiver
via a telecommunication system.
Figure 2 shows a configuration using a power line carrier link.
Figures 1 and 2 apply to teleprotection systems transmitting and receiving frequency shift
keyed carrier or normally quiescent signals.
Figure 3 shows a configuration in which digital teleprotection is directly connected via an
optical fibre.
Figure 4 is an alternative arrangement where the digital teleprotection is connected to a digital
telecommunication system via multiplexing equipment.
60834-1 IEC:1999 – 15 –
Figures 3 and 4 apply to teleprotection systems transmitting and receiving digital data.
Figures 1 to 4 serve only as examples. Other configurations are possible but are not shown.
1.5 Definitions
For the purposes of this part of IEC 60834, the following definitions apply. Refer also to figure 5
which clarifies the relationship between terms in use.
1.5.1
protection
the 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 – The term "protection" is a generic term for protection equipments or protection systems.
NOTE 2 – 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 – Protection does not include items of power system plant provided, for example, to limit overvoltages 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.
[IEV 448-11-01]
1.5.2
protection equipment
an equipment incorporating one or more protection relays and, if necessary, logic elements
intended to perform one or more specified protection functions
NOTE – A protection equipment is part of a protection system.
Example: Distance protection equipment, phase comparison protection equipment. (One-phase
comparison equipment is part of one line-end of a phase comparison protection system.)
[IEV 448-11-03]
1.5.3
protection system
an arrangement of one or more protection equipments, and other devices intended to perform
one or more specified protection functions
NOTE 1 – 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 – The circuit-breaker(s) are excluded.
[IEV 448-11-04]
60834-1 IEC:1999 – 17 –
1.5.4
selectivity of protection
the ability of a protection to identify the faulty section and/or phase(s) of a power system
[IEV 448-11-06]
1.5.5
unit protection
a protection whose operation and section selectivity are dependent on the comparison of
electrical quantities at each end of the protected section
NOTE – In the USA, the term "unit protection" designates the protection provided for an electrical generator.
[IEV 448-11-09]
1.5.6
non-unit protection
a protection whose operation and section selectivity are dependent on the measurement of
electrical quantities at one end of the protected section by the measuring relays and, in some
cases, on the exchange of logic signals between the ends
NOTE – The section selectivity of non-unit protection may depend upon its setting, particularly with regard to time.
[IEV 448-11-10]
1.5.7
distance protection
a non-circuit protection whose operation and selectivity depend on local measurement of
electrical quantities from which the equivalent distance to the fault is evaluated by comparing
with zone settings
[IEV 448-14-01]
1.5.8
underreach
the condition of a protection, generally distance protection, when the shortest zone setting
corresponds to a reach shorter than the protected section
[IEV 448-14-05]
1.5.9
overreach
the condition of a protection, generally distance protection, when the shortest zone setting
corresponds to a reach longer than the protected section
[IEV 448-14-07]
1.5.10
teleprotection equipment
equipment specially designed to be used in conjunction with a protection system. The
teleprotection equipment, which is connected to a telecommunication link between both ends of
the protected circuit, transforms the information given by the protection equipment into a form
suitable for transmission
60834-1 IEC:1999 – 19 –
1.5.10.1
teleprotection system
system composed of teleprotection equipment and an associated telecommunication system
between the ends of a protected circuit
1.5.10.2
teleprotection channel
frequency band or bit rate provided by the telecommunication system in order to permit the
transmission of protection signals
NOTE – The teleprotection channel may be either analogue or digital. In an analogue teleprotection channel the
instantaneous signal varies continuously, even though the information is of a digital nature. In a digital
teleprotection channel only certain discrete levels (usually two or three) are permitted. In a digital teleprotection
system, it is usual to convey bit timing information synchronously with the data. This timing information can be
either integrated with the data or transmitted as a separate clock signal depending on the interface type. Timing
information should be regarded as part of the teleprotection channel.
1.5.10.3
telecommunication system – telecommunication link
system composed of telecommunication equipment and the associated physical link required to
transmit information signals over a distance
1.5.11
pilot wire protection
protection associated with telecommunication using metallic wires
[IEV 448-15-04]
1.5.12
power-line-carrier protection
protection associated with telecommunication using power-line carrier
[IEV 448-15-05]
1.5.13
microwave link protection
protection associated with telecommunication using a microwave link
[IEV 448-15-06]
1.5.14
communication-aided distance protection
distance protection which utilises communication to improve its performance
1.5.15
permissive protection
a protection, generally distance protection, in which the receipt of a signal permits the local
protection to initiate tripping
[IEV 448-14-09]
1.5.16
permissive underreach protection (PUP)
protection, generally distance protection, using telecommunication, with underreach protection
at each section end and in which a signal is transmitted when a fault is detected by the
underreach protection. Receipt of the signal at the other end initiates tripping if other local
permissive protection at the other end has detected the fault
[IEV 448-15-11]
60834-1 IEC:1999 – 21 –
1.5.17
permissive overreach protection (POP)
protection, generally distance protection, using telecommunication, with overreach protection at
each section end and in which a signal is transmitted when a fault is detected by the overreach
protection. Receipt of the signal at the other end permits the initiation of tripping by the local
overreach protection
[IEV 448-15-16]
1.5.18
accelerated underreach protection (AUP)
protection, generally distance protection, using telecommunication, with underreach protection
at each section end and in which a signal is transmitted when a fault is detected by the
underreach protection. Receipt of the signal at the other end permits a sequential
measurement by an overreach zone to initiate tripping
[IEV 448-15-13]
1.5.19
blocking protection
a protection, generally distance protection, in which the receipt of a signal blocks the local
protection from initiating tripping
[IEV 448-14-10]
1.5.20
blocking overreach protection (BOP)
protection, generally distance protection, using telecommunication, with overreach protection at
each section end and in which a signal is transmitted when a reverse external fault is detected.
Receipt of the signal at the other end blocks the overreach protection at that end from initiating
tripping
[IEV 448-15-14]
1.5.21
longitudinal differential protection
protection the operation and selectivity of which depend on the comparison of magnitude or the
phase and magnitude of the currents at the ends of the protected section
[IEV 448-14-16]
1.5.22
phase comparison protection
protection whose operation and selectivity depend on the comparison of the phase of the
currents at each end of the protected section
[IEV 448-14-18]
1.5.23
intertripping
the tripping of circuit-breaker(s) by signals initiated from protection at a remote location
independent of the state of the local protection
[IEV 448-15-08]
60834-1 IEC:1999 – 23 –
2 Characteristics of command type teleprotection systems
The following subclauses deal with the terms used in the description and/or specification of
teleprotection systems (see also 3.3.1).
2.1 Types of teleprotection command schemes
a) Permissive tripping schemes (see 1.5)
This term refers to schemes where the received command initiates tripping in conjunction
with a local protection equipment. Command channels of this type can operate in an audio
frequency band, a PLC frequency band or at a digital bit rate. The channel is often
designed with the premise that dependability of operation should be high even under
conditions when, due to a power system disturbance, the telecommunication medium may
be adversely affected.
b) Intertripping schemes (direct or transfer tripping) (see 1.5)
This term refers to schemes where the received command initiates tripping without
qualification by local protection. Intertrip channels utilise similar principles to permissive trip
channels; however, security against unwanted operation and dependability of correct
operation are prime requirements. Speed of operation is usually sacrificed to meet security
and dependability requirements, particularly in analogue systems.
c) Blocking protection schemes (see 1.5)
This term refers to schemes where the received command blocks the operation of local
protection. These channels utilise similar principles to permissive trip channels; however,
dependability of operation and speed are prime requirements.
2.2 Overall operating time of teleprotection systems
(telecommunication circuit included)
The overall operating time T is the time elapsed between the instant of change in state at the
command input and the instant of the corresponding change in state at the command output,
including propagation time and additional delay due to noise.
The overall operating time of a teleprotection system influences the fault clearance time (see
figure 6).
NOTE – Fault clearance time T as shown in figure 6 is typical only.
c
2.3 Transmission times (telecommunication circuit excluded)
The transmission time of a teleprotection system is the time elapsed between the instant of
change in state at the command input and the instant of the corresponding change in state at
the command output, excluding propagation time.
The nominal transmission time T is the transmission time measured under noise-free
transmission conditions (see also 4.3.3).
The maximum actual transmission time T is the maximum transmission time encountered
ac
under noisy conditions for a defined dependability and signal-to-noise (S/N) ratio or bit error
rate (BER).
60834-1 IEC:1999 – 25 –
The transmission time is measured with continuous white noise or with random bit errors
applied to the transmission path depending upon the type of teleprotection system. For various
S/N ratios or BERs the maximum actual transmission time T (typically 2 ms to 65 ms, as
ac
shown in figure 6) is determined.
This method of testing corresponds as closely as possible to actual conditions.
Clamping or inhibit actions used in some teleprotection equipment may influence the
transmission time due to noise.
2.4 Security
Security relates to the ability to prevent interference and noise from generating a command
state at the receiving end when no command signal is transmitted.
For practical reasons the probability of an unwanted command P is normally measured
uc
(see 4.3.1.1 and 4.3.2.1).
Security is then given by
1 – P
uc
An unwanted command is a command that occurs at the receiving end for a time longer than a
specified duration when no such command has been transmitted.
If the duration of an unwanted command state, T , is longer than a specified duration, it will be
uc
seen as an actual command. With permissive trip schemes, the risk of an unwanted tripping
action is generally low, while in intertripping (direct tripping) schemes each unwanted command
will lead to an unwanted tripping action.
With blocking schemes, an unwanted command may lead, depending upon its duration T ,
uc
either to a delayed trip or to a failure to trip (lack of dependability of the protection scheme).
For analogue teleprotection systems, the probability of an unwanted command is measured by
applying bursts of white noise to the transmission path. The probability of an unwanted
command P is determined, for the worst case S/N ratio, from the ratio of the number of
uc
unwanted commands received to the number of noise bursts of specified duration that have
been applied.
The application of noise bursts corresponds as nearly as possible to actual conditions
(e.g. circuit-breaker and disconnector operations, arcing noise, etc.) and enables a comparison
of the results obtained with different equipment (see 4.3). It is essential that the unwanted
command rate is measured with bursts of noise since the receiver may block its output after a
certain time in the presence of continuous noise. The interval between successive noise bursts
shall be sufficient so as to allow the receiver to recover.
60834-1 IEC:1999 – 27 –
For digital teleprotection systems, security is tested with bursts of random errors. This method
is required in order to test teleprotection equipment that incorporate inhibit circuits designed to
operate at certain measured BERs. The interval between bursts can be reduced to test
teleprotection equipment without inhibit or blocking circuits. An additional test is required in
order to ascertain whether unwanted commands occur following the complete loss or
reintroduction of the digital teleprotection channel. The probability of an unwanted command
P is determined, for various BERs, from the ratio of the number of unwanted commands
uc
received to the number of error bursts.
2.5 Dependability
Dependability relates to the ability to issue and receive a valid command in the presence of
interference and/or noise.
For practical reasons the probability of a missing command P is normally measured
mc
(see 4.3.1.2 and 4.3.2.2).
Dependability is then given by
1 – P
mc
When a command is sent from the transmitting end, it is considered a missing command in the
following cases:
a) command state at the receiving end is absent or takes place with an excessive delay;
b) command state at the receiving end is shorter than a specified duration.
Cases a) and b) give rise to a failure to trip or a delayed trip in an intertripping (direct tripping)
or permissive tripping scheme.
In a blocking scheme, an unwanted operation is likely to occur in the presence of an external
fault condition (lack of security of the protection scheme).
The probability of a missing command is measured by applying pulsed white noise or pulsed
random bit errors to the transmission path. The probability of a missing command P is then
mc
determined, at various S/N ratios or BERs, from the ratio of the number of commands which
are not received within a specified time (and are of a specified duration, see b) above) to the
number of transmitted commands. Continuous white noise, or continuous random bit errors,
may be used for the test when the blocking mechanism of the teleprotection receiver is not
employed or is disabled.
This method corresponds as far as possible to actual conditions; furthermore, it offers the
advantage that results obtained with different equipment can be easily compared.
60834-1 IEC:1999 – 29 –
2.6 Nominal frequency band or bit rate
For analogue teleprotection equipment, the nominal frequency band is given by the bandwidth
required by the teleprotection equipment to perform its stated functions, including any noise
sensing requirement. The bandwidth used affects the transmission time. In analogue
teleprotection, the frequency band used has a bearing on other services using the same
communication channel.
For digital teleprotection equipment, the bandwidth of the channel needs to be sufficiently large
to support the bit rate which the particular equipment utilises. The bit rate used affects the
transmission time.
2.7 Nominal impedance
The nominal impedance of teleprotection equipment is defined as the input and output impedance
of the equipment measured at its nominal frequency band. The impedance of voice frequency
teleprotection equipment is normally 600 Ω. In the case of power line carrier channels the nominal
impedance shall be the same as that for other power line carrier equipment. Typical values are
50 Ω and 75 Ω unbalanced, and 150 Ω balanced.
For digital teleprotection equipment the nominal impedance will depend on the specified digital
interface being used.
2.8 Guard signals/Command signals
The guard signal is a signal that is transmitted to monitor the integrity of the teleprotection
system and it effectively supervises the channel in terms of the signal quality. Other monitoring
is often also employed. When present, the guard signal inhibits any command output of the
teleprotection receiver.
The command signal is a signal that is transmitted to produce a change of state at a remote
location. The requirements for the command signal are dependent upon the type of scheme as
defined in 2.1.
2.9 Levels of guard signals (analogue systems only)
In the case of equipment dedicated to teleprotection, the level of a guard signal is related to the
power output of the transmitter in order to comply with its peak envelope power (PEP). In the
case of PLC voice frequency equipment, other services may be carried on the same link on a
multi-purpose basis. When a starting relay operates, the guard signal may be boosted to the
full power of the transmitter, cutting other signals.
Boosting of the guard signal is also employed on some dedicated systems, such as quiescent
systems or those employing PLC high-frequency teleprotection equipment.
2.10 Levels of command signals (analogue systems only)
In the case of equipment dedicated to teleprotection the level of the command signal, as well
as the level of the guard signal, are related to the PEP of the transmitter.
60834-1 IEC:1999 – 31 –
In all cases, where power boosting is applied to the guard signal, the command signal is
treated in the same fashion. In many cases the command signal only may be boosted.
3 Requirements for command type teleprotection systems
3.1 General equipment interface requirements
The following requirements apply to the interface between protection equipment and
teleprotection equipment as well as to the interface between teleprotection equipment and the
telecommunication system. These interfaces a) and b) are defined in figures 1, 2, 3 and 4. The
requirements apply equally when the various types of equipment are integrated as well as
separated from each other.
If the protection equipment and the teleprotection equipment form a combined system installed
in the same enclosure in the same location, the requirements for interface a) may not be
applicable. If the teleprotection equipment and the telecommunication equipment are part of a
common apparatus and are installed in the same bay in the same location, the requirements
for interface b) may not be applicable.
3.1.1 Insulation
The insulation withstand tests are covered in 3.1.2.
3.1.2 Insulation withstand voltages
The requirements for insulation withstand voltages are in accordance with IEC 60870-2-1.
All input and output circuits (including power supply terminals) shall sustain without any
damage the withstand voltages reported for the following classes:
VW1 for all transmit and receive terminals (interface b) shown in figures 1 and 4.
VW2 for all d.c. terminals below 60 V.
VW3 for all other terminals up to 250 V.
For the sake of clarity the specifications of the aforesaid classes are given below.
Table 1
Power frequency
1,2/50 μs impulse voltage
Class withstand voltage
(kV peak)
(kV r.m.s. for 60 s)
VW1 0,5 1
VW2 1 2
VW3 2,5 5
60834-1 IEC:1999 – 33 –
Other classes shall be agreed between user and manufacturer.
The insulation resistance of the circuits under test shall not be less than 100 MΩ for any
temperature less than 35 °C and relative humidity less than 75 %.
The tests shall be carried out with the equipment under test turned on, but with the power
connections disconnected.
3.1.3 Damped oscillatory waves- disturbance level
In order to test the immunity of the equipment to disturbances caused by switching phenomena or
faults on the HV network, the following test, which corresponds to test A.2.5 of IEC 60870-2-1,
shall be carried out.
All input and output circuits (including power supply terminals), shall sustain, without any
damage or unwanted command, damped oscillatory waveforms applied to the relative
terminals, both in differential and in common mode. For communication interfaces, only the
common mode tests shall be carried out.
The standard peak value of the test voltage shall be 2,5 kV , corresponding to a severity
peak
level 3 according to table 12 of IEC 60870-2-1.
[Severity level 3: equipment installed in an environment which has no special protection;
equipment of controlled stations or remote terminal units located in residential and in industrial
areas.]
Differential mode tests shall be carried out at half common mode level.
The tests shall be carried out under operating conditions.
3.1.4 Fast transient bursts – disturbance level
In order to test the immunity of the equipment to disturbances caused by the switching of small
inductive loads, relay contact bouncing or switching of HV switchgear, the following test, which
corresponds to test A.2.3 of IEC 60870-2-1, shall be carried out.
All input and output circuits (including power supply terminals) shall sustain, without any
damage or unwanted command, fast transient bursts applied to the relative terminals both in
differential and in common mode. For communication interfaces, only the common mode tests
shall be carried out.
Failure modes shall be evaluated in accordance with the criteria given in IEC 60870-2-1 and
the class of failure shall be agreed between manufacturer and user.
The standard peak value of the test voltage shall be 2,0 kV , corresponding to a severity
peak
level 3 according to table 12 of IEC 60870-2-1.
[Severity level 3: equipment installed in an environment which has no special protection:
equipment of controlled stations or remote terminal units located in residential and in industrial
areas.]
60834-1 IEC:1999 – 35 –
However, where agreed between manufacturer and user, the peak value of the test voltage
shall be 4,0 kV corresponding to a severity level 4 according to table 12 of IEC 60870-2-1.
peak
Differential mode tests shall be 1 kV or 2 kV depending on the severity level specified.
peak peak
The tests shall be carried out under operating conditions.
3.1.5 Electrostatic discharge – disturbance levels
In order to test the immunity of the equipment to electrostatic discharges between a charged
operator and the equipment or between two nearby objects, the following test, which
corresponds to test A.3.1 of IEC 60870-2-1, shall be carried out.
The standard peak value of the test voltage (contact discharge) shall be 8,0 kV
peak
corresponding to a severity level 4 according to table 13 of IEC 60870-2-1. Air discharge shall
be used where contact discharge cannot be applied. The peak value of the test voltage for air
discharge is 15 kV for severity level 4.
peak
[Severity level 4: equipment of controlled stations and remote terminal units installed in
uncontrolled areas.]
The equipment shall sustain, without any damage or unwanted command, the application of the
test voltage.
The test shall be carried out under operating conditions.
3.1.6 Radiated electromagnetic field disturbances
In order to test the immunity of the equipment to disturbances caused by electromagnetic fields
generated by portable radio transceivers or any other device, the following test, which
corresponds to test A.5.1 of IEC 60870-2-1, shall be carried out.
The test value of the electromagnetic field shall be 10 V/m, corresponding to severity level 3
according to table 15 of IEC 60870-2-1.
[Severity level 3: equipment installed in an environment with severe radiation; equipment of
controlled stations or remote terminal units located in residential and industrial areas, or in
electrical plants.]
The equipment shall sustain, without any damage or unwanted command, the application of the
test electromagnetic field.
The test shall be carried out under operating conditions in an open rack configuration.
3.1.7 RF disturbance emission
It is considered necessary to verify the limits of electromagnetic disturbance generated by the
equipment that may affect the performance of other components of the system or influence
the external environme
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