Ormazabal ekor.rpa Series Instruction manual

LIB
ekor.rpa
Protection, metering and control
multifunction unit
General Instructions
IG-267-EN, version 01, 07/04/2017

In view of the constant evolution in standards and design, the characteristics of the elements contained in this manual are subject
to change without prior notice. These characteristics, as well as the availability of components, are subject to confirmation by
Ormazabal.
CAUTION!
When medium-voltage equipment is operating, certain components are live, other parts may be in movement and some may
reach high temperatures. Therefore, the use of this equipment poses electrical, mechanical and thermal risks.
In order to ensure an acceptable level of protection for people and property, and in compliance with applicable environmental
recommendations, Ormazabal designs and manufactures its products according to the principle of integrated safety, based on
the following criteria:
• Elimination of hazards wherever possible.
• Where elimination of hazards is neither technically nor economically feasible, appropriate protection functions are
incorporated in the equipment.
• Communication about remaining risks to facilitate the design of operating procedures which prevent such risks,
training for the personnel in charge of the equipment, and the use of suitable personal protective equipment.
• Use of recyclable materials and establishment of procedures for the disposal of equipment and components so
that once the end of their service lives is reached, they are duly processed in accordance, as far as possible, with the
environmental restrictions established by the competent authorities.
Consequently, the equipment to which the present manual refers complies with the requirements of section 11.2 of Standard
IEC 62271-1. It must therefore only be operated by appropriately qualified and supervised personnel, in accordance with the
requirements of standard EN 50110-1 on the safety of electrical installations and standard EN 50110-2 on activities in or near
electrical installations. Personnel must be fully familiar with the instructions and warnings contained in this manual and in other
recommendations of a more general nature which are applicable to the situation according to current legislation[1].
The above must be carefully observed, as the correct and safe operation of this equipment depends not only on its design but also
on general circumstances which are in general beyond the control and responsibility of the manufacturer. More specifically:
• The equipment must be handled and transported appropriately from the factory to the place of installation.
• All intermediate storage should occur in conditions which do not alter or damage the characteristics of the equipment
or its essential components.
• Service conditions must be compatible with the equipment rating.
• The equipment must be operated strictly in accordance with the instructions given in the manual, and the applicable
operating and safety principles must be clearly understood.
• Maintenance should be performed properly, taking into account the actual service and environmental conditions in
the place of installation.
The manufacturer declines all liability for any significant indirect damages resulting from violation of the guarantee, under any
jurisdiction, including loss of income, stoppages and costs resulting from repair or replacement of parts.
Warranty
The manufacturer guarantees this product against any defect in materials and operation during the contractual period. In the
event that defects are detected, the manufacturer may opt either to repair or replace the equipment. Improper handling of this
equipment and its repair by the user shall constitute a violation of the guarantee.
Registered Trademarks and Copyrights
All registered trademarks cited in this document are the property of their respective owners. The intellectual property of this manual
belongs to Ormazabal.
[1] For example, in Spain the “Regulation on technical conditions and guarantees for safety in high-voltage electrical installations” – Royal Decree
337/2014 is obligatory.

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General Instructions
ekor.rpa
Contents
Contents
1. General description ..................................................5
1.1. General operating features ...................6
1.2. Components.................................7
1.2.1. Electronic relay ..............................8
1.2.2. Current sensors ..............................9
1.2.3. Voltage sensors ..............................9
1.2.4. “Binox” bistable tripping device and
tripping coil ................................10
1.3. Functionality of the unit.....................10
1.4. Communications............................11
2. Applications .............................................................12
2.1. Remote control of transformer and
distribution substations .....................12
2.2. Automatic reclosing of lines .................12
2.3. Line protection with circuit-breaker..........13
2.4. Transformer protection......................14
2.5. Automatic transfer . . . . . . . . . . . . . . . . . . . . . . . . . .16
2.6. Detection of phase with earthing............16
2.7. Protection and control of
MV interconnection stations.................17
2.8. Energy balances ............................17
3. Metering functions ..................................................18
3.1. Current and voltage metering ...............18
3.2. Power meterings............................19
3.3. Energy meter ...............................19
4. Protection functions ................................................20
4.1. Overcurrent units ...........................20
4.1.1. Timed overcurrent units.....................20
4.1.2. Instantaneous overcurrent units.............21
4.1.3. Block diagram ..............................21
4.2. Ultra-sensitive earth.........................22
4.3. Directional units ............................23
4.3.1. Phase directional units ......................23
4.3.2. Neutral and sensitive neutral
directional units ............................24
4.4. Thermal image unit .........................25
4.4.1. Estimated thermal capacity..................26
4.4.2. Functionality................................27
4.4.3. Block diagram ..............................28
4.5. Broken conductor unit ......................29
4.5.1. Calculation of sequence currents ............29
4.5.2. Functionality................................32
4.5.3. Block diagram ..............................32
4.6. Voltage units ...............................33
4.6.1. Timed overvoltage units ....................34
4.6.2. Instantaneous overvoltage units.............34
4.6.3. Timed undervoltage units ...................35
4.6.4. Instantaneous undervoltage units ...........35
4.6.5. Block diagram ..............................36
4.7. Second harmonic blocking unit .............37
4.7.1. Functionality................................37
4.7.2. Block diagram ..............................39
4.8. Block by Imax.................................41
5. Detection, automation and control functions.......42
5.1. Recloser automation ........................42
5.1.1. Functionality................................42
5.1.2. VREF........................................42
5.1.3. Settings ....................................43
5.1.4. Recloser statuses............................43
5.2. Voltage presence/absence automation ......45
5.2.1. Functionality................................45
5.2.2. Settings ....................................45
5.2.3. Voltage presence/absence
automation statuses ........................45
5.3. Switch control ..............................46
5.3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
5.3.2. Settings ....................................46
5.3.3. Switch control statuses......................47
5.4. Remote control .............................47
6. Sensors......................................................................48
6.1. Current sensors .............................48
6.1.1. Functional characteristics
of current sensors...........................49
6.1.2. Vector sum/zero-sequence wiring ...........50
6.2. Voltage sensors .............................51
6.2.1. Bushing ....................................51
6.2.2. ekor.evt-c ..................................52
7. Technical characteristics of the equipment ...........53
7.1. Rated values ................................53
7.2. Mechanical design ..........................53
7.3. Insulation tests..............................54
7.4. Electromagnetic compatibility...............54
7.5. Climatic tests ...............................55
7.6. Mechanical tests ............................55
7.7. Power tests .................................55
7.8. CE Conformity ..............................55

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Contents General Instructions
ekor.rpa
8. Protection, metering and control models .............56
8.1. Description of models vs functions ..........56
8.1.1. ekor.rpa-110................................58
8.1.2. ekor.rpa-120................................58
8.1.3. ekor.rpa-100-v/ekor.rpa-100-p..............59
8.1.4. Relay configurator ..........................60
8.2. “v” ekor.rpa-110-v and ekor.rpa-120-v
type units...................................61
8.2.1. Functional description ......................61
8.2.2. Definition of digital inputs/outputs .........62
8.2.3. Installation in a cubicle......................63
8.2.4. Checking and maintenance .................64
8.3. “p” ekor.rpa-110-p and ekor.rpa-120-p
type units ..................................66
8.3.1. Functional description ......................66
8.3.2. Definition of digital inputs/outputs ..........67
8.3.3. Fuse protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
8.3.4. Installation in a cubicle......................71
8.3.5. Checking and maintenance .................72
9. User configuration settings.....................................73
9.1. Local protection and automation settings ...73
9.2. Date and time settings ......................79
9.3. Remote communication settings ............79
10. Log record.................................................................80
10.1. Fault report ................................80
10.1.1. Data capture logic ..........................80
10.1.2. Structure of the report ......................81
10.1.3. List of available signals .....................82
10.2. Event record ................................84
11. User interface ...........................................................85
11.1. Web server. Checking and
configuring parameters .....................85
11.1.1. Characteristics of the Web server ............85
11.1.2. Access to the Web server: Local and
remote access ..............................86
11.2. Keyboard/Display ..........................90
11.2.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90
11.2.2. Display screen ..............................91
11.2.3. Error codes .................................96
11.3. Fileserver in USB memory ...................97
11.3.1. Connection to the system ...................97
11.3.2. Use of the interface .........................98
11.3.3. ekor.soft-xml .............................100
12. Communications ................................................... 102
12.1. Physical medium: RS-485..................102
12.1.1. MODBUS protocol ........................ 102
12.1.2. PROCOME protocol ....................... 107
12.2. Physical medium: Ethernet ................110
12.3. Physical medium: Mini-USB................111
13. Annex ..................................................................... 112

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General Instructions
ekor.rpa
General description
1. General description
Within the ekor.sys family, the ekor.rpa range of protection,
metering and control units groups together a series of
multifunctional devices. Depending on the model, the
equipment can incorporate voltage and current functions,
along with automation functions, local/remote control,
etc. All these functions are related to current and future
automation, control and protection requirements in
switching and transformer substations.
As a result of new demands in supply quality, there is an
increasing need for automation in distribution networks
and for equipment to carry out metering and control
supervision functions for the switch in distribution cubicles.
The ekor.rpa-100 protection, metering and control units
have been designed to meet these needs, in accordance
with national and international standard requirements and
recommendations that are applied to each part that makes
up the unit:
• EN 60255, EN 61000, EN 62271-200, EN 60068, EN 60044.
• IEC 60255, IEC 61000, IEC 62271-200, IEC 60068, IEC 60044,
IEC 61958.
Integrating the ekor.rpa units in the Ormazabal cubicle
system allows specific products for requirements in different
facilities.
The ekor.rpa-100 units in the ekor.rpa range have outputs
to, either locally or remotely, open and close the switch
in the cubicle where it is installed. Furthermore, the
equipment series has inputs which receive the status of the
cubicle switch.
The ekor.rpa-100 units also have the following benefits
compared to conventional systems:
1. The remote control unit (RTU or Remote Terminal Unit)
andprotection areintegratedinthecubicle inacompact
manner, simplifying the solution and minimising the
need to install control boxes on the cubicles.
2. Delivering the complete integrated solution (cubicle +
relay + sensors) reduces handling of interconnections
when installing the cubicle in the network connection.
The only connection necessary is the medium-voltage
cables (MV). The possibility of wiring and installation
errors is removed, thus minimising commissioning time.
3. Voltage and current sensors are installed in the cubicle
cable bushing. Metering of V, I, P, Q and energies are
obtained without the need for voltage transformers.
4. All the units are factory installed, adjusted and checked;
each piece of equipment (relay + control + sensors)
also undergoes a comprehensive check before being
installed. The final unit tests are carried out once the
unit is incorporated in the cubicle before delivery.
5. Current metering is carried out by current sensors
with a high transformation ratio, making it possible for
the same equipment to detect a wide range of power
levels. This is possible thanks to the high sensitivity and
low noise of the relay's analogue channels.
Figure 1.1. Protection, metering and control units: ekor.sys family

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General description General Instructions
ekor.rpa
1.1. General operating features
All the relays of the ekor.rpa-100 series include a
microprocessor for processing the metering sensor signals.
They process voltage and current meterings and eliminate
the influence of transient states, calculate the magnitudes
required to ensure current and voltage protection functions,
automation, etc. At the same time they calculate the
efficient values of the electrical meterings that report the
instantaneous value of these parameters of the installation.
Figure 1.2. ekor.rpa-100 series relay
The ekor.rpa-100 relays are equipped with a keypad for
local display, set-up and operation of the unit, as well as
communication ports to handle these functions from a PC,
either locally or remotely. The ergonomic keyboard menus
have been designed to make use as intuitive as possible.
Current metering is carried out via high transformation
ratio current sensors. These transformers or current sensors
maintain the accuracy class in all of their rated range.
Voltage metering is normally by capturing the voltage
signal using a capacitor divider built into the cubicle's
bushing. There is an option of installing ekor.evt-c external
capacitive voltage sensors for applications which require
high-voltage metering precision, such as applications with
MV network energy meters.
The different interfaces, local (display) or remote (Web), also
provide settings parameters, logs, events, etc., in addition
to instantaneous values for metering of currents, voltages,
powers and energies.
From a maintenance perspective, the ekor.rpa-100 units
have a series of features that reduce the time and the
possibility of errors in the test and service restoration tasks.
Among the main characteristics, the most prominent are
the large diameter toroidal-core current transformers
installed in the cubicle bushing, their built-in test bars
(for easier checking), and accessible terminal blocks for
current or voltage injection tests as well as for checking
the relay inputs and outputs. This configuration enables a
comprehensive testing of the unit.

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General Instructions
ekor.rpa
General description
1.2. Components
The parts which make up the ekor.rpa-100 protection,
metering and control series are the electronic relay, voltage
and current sensors, auxiliary circuits (terminal block and
wiring), the bistable release and the tripping coil.
1Terminal block
2ekor.rpa electronic relay
3Voltage and current sensors
Figure 1.3. Parts of the assembly of ekor.rpa-100 in cubicle

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General description General Instructions
ekor.rpa
1.2.1. Electronic relay
The electronic relay has a keyboard and display to set and
view the protection and control parameters. Moreover, the
display provides information of the system's meterings,
alarms and control signals in real time. The keyboard
includes a seal on the <<SET>> key to ensure that once the
settings have been made they cannot be changed unless
the seal is broken.
The protection trips are registered on the display with the
following parameters:
• Trip unit
• The phasor at the moment of tripping (currents and
voltages).
• Tripping time. The time passing from start-up to tripping
of the unit.
• The time and date the event occurred.
Unit errors are also permanently displayed. Furthermore, it
is possible to check the fault reports using the front USB port
by connecting a PC to this port and using the implemented
folder system.
The “ON” LED is activated when the equipment receives
power from an external source and flashes quickly when
the relay starts up. This LED will flash less frequently
once the microprocessor has checked that the status of
the equipment is correct and all the protection units are
active. In this situation, the unit is operational to carry out
protection functions.
The voltage and current analogue signals are conditioned
internally by small and very accurate transformers that
isolate the electronic circuits from the rest of the installation.
The system has, in all its variants, 9 inputs and 4 outputs.
Both the inputs and the outputs are protected from
unwanted enabling/disabling.
The unit has 2 rear Ethernet ports for configuration, a
front mini-USB port for maintenance, and two rear RS-485
communications ports for remote control. The standard
communication protocols for all models are MODBUS and
PROCOME.
1"ON" signalling LED
2Metering and parameter setting display
3SET key
4Keyboard for scrolling through screens
5Front mini-USB communication port
Figure 1.4. Description of the elements available on the front of the
ekor.rpa-120 relay

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General Instructions
ekor.rpa
General description
1.2.2. Current sensors
The current sensors are toroidal-core current transformers
with a 300/1 A or 1000/1 A or 2500/1 ratio, depending on
the models. These transformers cover the entire operation
range of Ormazabal cubicles, from rated currents 5A up to
2500 A.
The phase toroidal transformers are factory-installed in
the cubicle bushings, which significantly simplifies on-site
assembly and connection. This way, once the medium-
voltage cables are connected to the cubicle, the installation
protection is operational. Installation errors of the sensors,
due to earth grids, polarities, etc., are removed upon
installation and checked directly at the factory.
All the current sensors have an integrated protection
against the opening of secondary circuits, which prevents
overvoltages.
1Bushing
2Current sensors
Figure 1.5. Location of the current sensors
1.2.3. Voltage sensors
Cubicle voltage metering is carried out using a capacitor
divider incorporated in the cubicle’s bushing, which ensures
a precision of ± 5 % in the worst case scenario.
Ormazabal ekor.evt-c capacitive sensors can be used
for greater precision. These are capacitor divider voltage
sensors for gas-insulated cubicles. They are designed to
allow assembly in both separableT-connectors and busbars.
Their operation is autonomous and passive (without
external auxiliary supply), with low-voltage analogue
output and low power applicable directly to the metering
systems without prior conditioning, for installation in
medium-voltage automation and supervision systems in
networks up to 36 kV. It can also measure partial discharges
and establish communication via PLC.
Figure 1.6. ekor.evt-c voltage sensors

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General description General Instructions
ekor.rpa
1.2.4. “Binox” bistable tripping device and tripping coil
The "Binox" bistable trigger is a precision electromechanical
actuator which is sealed with its own reinforcement and
integrated in the switch driving mechanism. This release
acts upon the switch when there is a protection trip. It is
characterised by the low actuation power (high energy
efficiency) it requires for tripping. This energy is delivered in
the form of a pulse from the relay in a controlled manner to
ensure the proper operation of the release and the opening
of the switch.
The trials and tests passed by the ekor.rpa-100 unit set and
cubicle, along with quality assurance in manufacture, mean
this is a highly reliable element in the tripping chain. The
solutions presented by Ormazabal with ekor.rpa-100 units
have this tripping device installed as standard.
Figure 1.7. “Binox” Tripping coil
The operations ordered by the ekor.rpa-100 unit digital
outputs are performed by means of conventional tripping
coils. This way, a redundant and therefore more reliable
operational system is achieved.
1.3. Functionality of the unit
The functionality of the assembly as a unit (MV cubicles for
protection, metering and control, sensors, and protection
and metering transformers) is validated in a test plan carried
out in an in-house controlled environment.
To achieve this, Ormazabal counts on the CIT, its Research
and Technology Centre, which represents an essential
instrument in R&D, in order to capture and improve existing
technologies and carry out research into new ones.
The CIT facilities offer services to the science and technology
sector in order to carry out research, development and type
tests both for Ormazabal's business unit products and also
for the rest of the electricity sector.
The CIT is made up mainly of:
1. HPL: Electrotechnical power laboratory, with the goal
of identifying, acquiring and disseminating process
technologies and strategic products within Ormazabal.
2. UDEX: Demonstration and experimentation unit
consisting of a fully configurable, independent
medium-voltage singular experimentation network to
allow tests for new technologies, products and services
to be developed and carried out in a safe, controlled
environment.

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General Instructions
ekor.rpa
General description
1.4. Communications
All the relays of the ekor.rpa-100 units have two TCP/IP
connection Ethernet ports and a Web server for
configuration. They also have a front mini-USB port for
maintenance and two rear ports with serial communication
RS-485 twisted pair (COM0 and COM1) for remote control.
The standard communication protocols implemented in all
equipment are MODBUS in RTU transmission mode (binary)
and PROCOME, through the rear RS-485 COM0 port fitted in
these units.
Optionally, the ekor.rpa-120 model also has a bus for
temperature sensor connection.
The ekor.rpa-100 relays can be interconnected to other
units in the ekor.sys family, as shown in the image below.
1ekor.ccp
2ekor.bus
3ekor.rci
4ekor.rpa
5ekor.rpt
6ekor.rpg
Figure 1.8. Intercommunicated units of the ekor.sys family

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Applications General Instructions
ekor.rpa
2. Applications
2.1. Remote control of transformer and distribution substations
The ekor.rpa-100 protection, metering and control units
makeitpossibleto handleremote controlapplications ofthe
transformer and switching substations, by implementing
the control and monitoring of each switch through the
units associated with each functional unit.
Figure 2.1. Remote-controlled switching substation
The use of a remote control terminal and ekor.rpa-100 units
enable the user to visualise and operate each functional
unit remotely thanks to the inputs and outputs fitted for
this purpose.
Figure 2.2. Layout of dierent stations in the network
Units that include this remote control function:
Unit Type of cubicle
ekor.rpa-100 type = pFuse-combination switch
ekor.rpa-100 type = vCircuit-breaker
Table 2.1. Remote control function units
The remote controlling applications complement the
ekor.rci integrated control unit associated to feeder
functions (see Ormazabal document IG-158).
2.2. Automatic reclosing of lines
The reclosing function performs the automatic reclosing of
lines once the protection unit has commanded the trip and
the switch has opened.
This function is always associated with Ormazabal circuit-
breaker cubicles.
The protection units with automatic reclosing have a series
of advantages over protections without reclosing:
• They reduce the time in which electrical power is
interrupted.
• They avoid the need to locally re-establish the service in
substations without remote control for transient faults.
• They reduce the fault time using a combination of fast
switch trips and automatic reclosings, which results in
lesser damage caused by the fault and generates a lower
number of permanent faults derived from transient faults.
The unit which includes this function is:
Unit Type of cubicle
ekor.rpa-100 type = vCircuit-breaker
Table 2.2. Recloser function unit

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Applications
2.3. Line protection with circuit-breaker
The purpose of the line protection is to isolate this part
of the network in case of fault, without it affecting the
rest of the lines. In a general way, it covers any faults that
originate between the substation, transformer substation
or switching substation and the consumption points.
Figure 2.3. Feeder protection functions in ekor.rpa-100 relays
The types of fault that occur in these areas of the network
depend primarily on the nature of the line, overhead line or
cable and the neutral used.
In networks with overhead lines, the majority of faults are
transient, which makes many line reclosings effective; in
these cases, the reclosing function associated with circuit-
breakers is used.
This is not the case for underground cables where faults are
usually permanent.
On the other hand, in case of phase-to-earth faults in
overhead lines, when the ground resistance is very high,
the zero-sequence fault currents have a very low value In
these cases, an ‘ultrasensitive’ neutral current detection is
required.
The underground cables have earth coupling capacities,
which causes the single phase faults to include capacitive
currents. This phenomenon makes detection difficult in
isolated or resonant earthed neutral networks and thus
requires the use of the directional function.
In ekor.rpa-100 units, model ekor.rpa-110, line protection
is carried out mainly by the following functions:
• 50 ≡Instantaneous overcurrent relay. Protects against
short-circuits between phases.
• 51 ≡Inverse time overcurrent relay. Protects against
excessive overloads, which can deteriorate the
installation.
• 51_2 ≡Inverse time overcurrent relay II. Additional
step to protect against excessive overloads, which can
deteriorate the installation.
• 50N ≡Instantaneous earth overcurrent relay. Protects
against phase-to-earth short-circuits.
• 51N ≡Inverse time earth overcurrent relay. Protects
against highly resistive faults between phase and earth.
• 51_2_N ≡Inverse time earth overcurrent relay II.
Additional step to protect against highly resistive faults
between phase and earth.
• 50NS ≡Instantaneous sensitive earth overcurrent
relay. Protects against phase to earth short-circuits of
very low value.
• 51NS ≡Inverse time sensitive earth overcurrent
relay. Protects against highly resistive faults between
phase and earth of very low value.
• 51_2_NS ≡Inverse time sensitive earth overcurrent
relay II. Additional step to protect against highly
resistive faults between phase and earth of very low
value.
• 2nd Harm. Block ≡Second harmonic blocking. Blocks
overcurrent units during transformer magnetisation
• 79 ≡Reclosing relay. Enables the automatic reclosing
of lines.

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Applications General Instructions
ekor.rpa
In addition, the ekor.rpa-100 equipment, ekor.rpa-120
model, also have the following functions:
• 67/67N and 67NS ≡Directional overcurrent relay,
directional earth fault relay and directional sensitive
earth fault relay. Phase, neutral and sensitive neutral
directional functions which are associated to their
corresponding overcurrent units, together allowing
directional overcurrent units.
• 49 ≡Machine or transformer thermal relay. Protects
against thermal overloads in lines which cannot be
detected by the overcurrent units.
• 46BC ≡Broken conductor detection. Detects open
lines, which are generally quite difficult to detect using
overcurrent units.
• 59/59N ≡Overvoltage and residual overvoltage
relay. Protects against phase and neutral overvoltages
in the lines with 2 units for each phase and neutral, one
timed and the other instantaneous.
• 27 ≡ Undervoltage relay. Protects against phase
undervoltages in the lines with 2 units for each phase,
one timed and the other instantaneous.
The units which provide the aforementioned functions are:
Unit Type of cubicle
ekor.rpa-100 type = vCircuit-breaker
Table 2.3. ekor.rpa-100-v
2.4. Transformer protection
The distribution transformers require various protection
functions. Their selection depends primarily on the power
and level of responsibility they have in the installation.
Figure 2.4. Transformer protection functions in ekor.rpa-100 relays

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General Instructions
ekor.rpa
Applications
The protection functions, available in models
ekor.rpa-110, which must be implemented to protect
distribution transformers with power ratings between 160
kVA and 2 MVA are the following:
• 50 ≡Instantaneous overcurrent relay. Protects against
short-circuits between phases in the primary circuit, or
high value short-circuit currents between phases on the
secondary side. This function is performed by the fuses
when the protection cubicle does not include a circuit-
breaker.
• 51 ≡Inverse time overcurrent relay. Protects
against excessive overloads, which can deteriorate the
transformer, or against short-circuits in several turns of
the primary winding.
• 51_2 ≡Inverse time overcurrent relay II. Additional
step to protect against excessive overloads, which can
deteriorate the transformer, or against short-circuits in
several turns of the primary winding.
• 50N ≡Instantaneous earth overcurrent relay. Protects
against phase to earth short-circuits or secondary
winding short-circuits, from the interconnections and
windings in the primary.
• 51N ≡Inverse time earth overcurrent relay. Protects
against highly resistive faults from the primary circuit to
earth or to the secondary circuit.
• 51_2_N ≡Inverse time earth overcurrent relay II.
Additional step to protect against highly resistive faults
from the primary circuit to earth or to the secondary.
• 50NS ≡Instantaneous sensitive earth overcurrent
relay. Protects against phase to earth short-circuits of
very low value.
• 51NS ≡Inverse time sensitive earth overcurrent
relay. Protects against highly resistive faults between
phase and earth of very low value.
• 51_2_NS ≡Inverse time sensitive earth overcurrent
relay II. Additional step to protect against highly resistive
faults between phase and earth of very low value. 2nd
Harm. Block ≡Second harmonic blocking. Blocks
overcurrent units during transformer magnetisation.
In addition, the ekor.rpa-100 equipment, ekor.rpa-120
models, also have the following functions:
• 67/67N and 67NS ≡Directional overcurrent relay,
directional earth fault relay and directional sensitive
earth fault relay. Phase, neutral and sensitive neutral
directional functions which are associated to their
corresponding overcurrent units, together allowing
directional overcurrent units.
• 49 ≡Machine or transformer thermal relay. Protects
against thermal overloads of transformers which cannot
be detected by the overcurrent units.
• 46BC ≡Broken conductor detection. Detects open
lines. Broken conductors are quite difficult to detect
using overcurrent units.
• 59/59N ≡Overvoltage relay and residual overvoltage
relay. Protects against phase and neutral overvoltages
in the lines with 2 units for each phase and neutral, one
timed and the other instantaneous.
• 27 ≡Undervoltage relay. Protects against phase
undervoltages in the lines with 2 units for each phase,
one timed and the other instantaneous.
The protection units that include the above mentioned
functions are:
Unit Type of cubicle
ekor.rpa-100 type = pFuse-combination switch
ekor.rpa-100 type = vCircuit-breaker
Table 2.4. ekor.rpa-100-p/ekor.rpa-100-v

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Applications General Instructions
ekor.rpa
2.5. Automatic transfer
The automatic transfer of lines with circuit-breakers
minimises power outages in loads fed by transformer or
switching substations with more than one incoming line,
thereby improving continuity of service.
Under normal conditions with voltage present on two
possible incoming lines, the switch selected as preferred
remains closed and the reserve one is opened. A voltage
drop in the preferred line will cause the switch of this line
to open and the reserve switch to close afterwards. Once
normality has been re-established in the preferred line, the
inverse cycle is performed, and the system returns to its
initial status.
Figure 2.5. Automatic transfer
2.6. Detection of phase with earthing
In networks with isolated or resonant earthed neutral, the
fault currents are very low. In the event of a fault in a system
of this type, the fault current may not reach the calibrated
threshold for overcurrent protection, and therefore this
fault may not be detected.
Function 59 is used instead of programmed logic for
detecting this type of fault, analysing both the installation’s
neutral voltage and its current.
Figure 2.6. Detection of phase with earthing

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General Instructions
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Applications
2.7. Protection and control of MV interconnection stations
In MV customers where an ekor.rpa-100 relay is installed,
either in protection cubicles with circuit-breaker or fuses
which protect the MV outgoing, information on this
outgoing can be sent to the SCADA both by the web and
via the MODBUS-TCP communications protocol.
The accessible information would be as follows:
• Cubicle position
• Trips
• Alarms
• Meterings:
- Voltage
- Current
- Power
- Energy
2.8. Energy balances
By including MV energy meterings in the ekor.rpa-100
relays, it is possible to analyse non-technical losses which
can be found between the Transformer Substation and
the LV consumption, in order to uncover possible fraudulent
use such as energy which has not been billed due to an
error in the LV equipment.
1ekor.rci
2ekor.ccp
3ekor.rpa
4Meters
Figure 2.7. ekor.rpa-100 unit measuring MV energies in a transformer
with private customers

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Metering functions General Instructions
ekor.rpa
3. Metering functions
3.1. Current and voltage metering
The unit has four current reading inputs (IA, IB, ICand INS)
and three voltage reading inputs (VA, VBand VC). Each of
them are conditioned and digitised in order to carry out the
calculation.
The design of the equipment and sensors, along with their
integration in the cubicle, form an assembly which works
as a single unit to achieve maximum immunity and quality
of the signal to be measured, both in the 50 Hz and 60 Hz
networks.
The signal transduction and conditioning stages are
designed to ensure the sensor and relay assembly
reproduces both the magnitude and the phase of the
current and voltage signals of the distribution network.
This ensures optimal performance in real-time applications,
with protection algorithms, in all operation conditions and
in supply quality or load monitoring meterings.
The samples obtained for INand VN, calculated by the sum
of samples of the corresponding phase signals, must be
added to the voltage and current inputs sampled directly.
These calculated signal characteristics are equivalent to
those obtained by vector sum of the conventional sensor
signals.
The meterings for supervision of current and voltage are
measured integrated for 1.28 seconds and represented in
phasorial mode (module + argument). Network load status
is therefore updated regularly.
The current and voltage meterings are:
• Line currents IA, IBand IC.
• Line voltage: UAB, UBC and UCA and Line voltages: VA, VB
and VC.
• Residual currents and voltages. Represented as: IN/INS
(3Io) and VN(3Vo).
Figure 3.1. Current and voltage metering
The final calibration is the overall calibration of sensors,
metering equipment, cabling and switchgear, and is
validated in an exhaustive test plan carried out in a
controlled environment which reproduces the reality of the
medium-voltage electrical distribution network.
All this process includes different scenarios:
• Maximum electromagnetic interference and temperature
rise scenarios of the assembly, carried out at rated
switchgear current.
• Maximum thermal variation scenarios, carried out in a
climate chamber between -10 °C and 60 °C.
• Scenarios with highly aggressive transient disturbance,
power and lightning impulse tests with medium-voltage
levels.
• etc.
These tests conclude in points such as: the ratio of the
number of turns of the current transformers, impedance
of the voltage reading inputs, etc. All this is tested and
validated on the final solution delivered to the customer.

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Metering functions
3.2. Power meterings
The powers which are monitored (locally or remotely) are
1.28 second integrated meterings of the calculated RMS
instantaneous values.
Accredited meterings in precision class guarantee reliability
in the values obtained.
The equipment acts as a metering station for load analysis
or electrical supply quality monitoring tasks. The monitored
meterings for active and reactive power are single-phase
and three-phase, and three-phase only for apparent power.
The meterings are made up of:
• Single-phase: Active PA, PB and PC and Reactive QA, QB
and QC.
• Three-phase: PT, QT and ST Powers and Power Factor
(P.F.).
3.3. Energy meter
Theequipmentisfittedwithan"Activeandreactiveelectrical
energy meter" which meets the particular requirements for
static energy meters. This is an indirect connection three-
phase meter which, along with the voltage and current
metering sensors, form a medium-voltage (MV) meter.
The energy meter accumulates 100 meterings of powers
P and Q integrated in a semicircle (1 second for 50Hz and
1.2 seconds for 60Hz). In total, there will be four meters:
three single-phase (A phase, B phase and C phase) and one
three-phase.
Each meter has two active energy records (E+ and E-) and
four reactive energy records (Q1, Q2, Q3 and Q4), each of
them 32 bits. These registers have a bit to indicate overflow
and a reset option by command.
Active powers are expressed in kilovolts-hour (kWh) and
reactive powers are expressed in kilovolt amperes reactive-
hour (kVArh).
aReactive
bInductive
cCapacitive
dGenerated
eConsumed
fActive
Active energy imported (in kWh): EA + , EB + , EC + and ET +
Active energy exported (kWh): EA - , EB - , EC - and ET -
Inductive reactive energy imported (kVArh): QA1, QB1, QC1 and QT1
Capacitive reactive energy imported (kVArh): QA2, QB2, QC2 and QT2
Inductive reactive energy exported (kVArh): QA3, QB3, QC3 and QT3
Capacitive reactive energy exported (kVArh): QA4, QB4, QC4 and QT4
Figure 3.2. Energies

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Protection functions General Instructions
ekor.rpa
4. Protection functions
4.1. Overcurrent units
The ekor.rpa-100 systems are fitted with the following
overcurrent protection units:
Phases:
• Six phase overcurrent timed units (3 x 51.3 x 51(2)).
• Three phase overcurrent instantaneous units (3 x 50).
Neutral (Calculated):
• Two neutral timed overcurrent units (1 x 51N, 1 x 51(2)
N).
• A neutral instantaneous overcurrent unit (1 x 50N).
Sensitive neutral (measured):
• Two sensitive neutral timed overcurrent units (1 x 51NS,
1 x 51(2)NS).
• A sensitive neutral instantaneous overcurrent unit (1 x
50NS).
4.1.1. Timed overcurrent units
The phase, neutral and sensitive neutral timed units start
up if the fundamental value of the magnitude for each unit
exceeds the value 1.05 times the adjusted start-up, and are
reset when this value is below 0.95 times the adjusted value.
Tripping takes place if the unit is started up for the time set.
This time may be adjusted by selecting different types of
curve, in accordance with IEC and ANSI Standards.
The curves implemented in the ekor.rpa-100 units are:
IEC CURVES
• IEC DT: Defined time
• IEC NI: Normally inverse curve
• IEC VI: Very inverse curve
• IEC EI: Extremely inverse curve
• IEC LTI: Long time inverse curve
• IEC STI: Short time inverse curve
ANSI CURVES
• ANSI LI: Long time inverse curve
• ANSI NI: Normally inverse curve
• ANSI VI: Very inverse curve
• ANSI EI: Extremely inverse curve
These curves are detailed in the ANNEX section.
The settings for the timed units are:
• Enabling the unit: Enable/disable the unit (ON/OFF).
• Starting up the unit: Unit starting current. Variable
ranges in accordance with current transformers used.
• Time curve: Curve type (IEC DT, IEC NI, IEC VI, IEC EI, IEC
LTI, IEC STI, ANSI LI, ANSI NI, ANSI VI, ANSI EI).
• Time index: Time index, also known as time dial (from
0.05 to 1.60). This setting applies to all curve types
except for IEC DT.
• Fixed time: Unit tripping time (from 0.00 s to 100.00 s).
This setting only applies to IEC DT type curves.
• Torque control: Directional tripping mask (OFF,
FORWARD or REVERSE). To indicate the direction for
tripping:
- OFF: Regardless of the direction, the relevant
overcurrent unit will trip if the overcurrent conditions
are met.
- FORWARD: The corresponding overcurrent unit
will trip whenever the overcurrent conditions are
met, and the directional unit will give the FORWARD
signal.
- REVERSE: The corresponding overcurrent unit will
trip whenever the overcurrent conditions are met,
and the directional unit will give the REVERSE signal.
This setting will only be found in ekor.rpa-100 units
model 120.