IEEE Power & Energy Magazine - March/April 2018 - 62

A new concept of substation developed jointly
with GE displays a pioneering smart substation concept
that enhances the control of the overall system.
protection, communication, control, and command services
will be more effective in terms of time response, selectivity,
accuracy, interoperability, electrical safety, and reliability.
We have selected Parallel redundancy Protocol for the station
bus and High availability seamless redundancy protocol for
the process bus. For the best results, low-power instrument current transformers (LPiTs) based on magneto-optical properties
should be simultaneously installed. This guarantees safety
for maintenance and provides good linearity in the transient
dynamic response when a fault occurs.
most of the primary parts should be equipped with embedded or external monitoring systems based on a large variety of
sensors. For instance, in the Poste intelligent project, disconnectors are equipped with a measure of low-voltage current
required to actuate the mechanical engine rotating the arms;

therefore, a loose or blocked arm can be monitored and warnings or alarms initiated. To achieve this, it is required that the
sensors are compliant with ieC 61850 or that a multiprotocols
gateway (iriG-B, moDBUs, ieC 61850) be installed. The
monitoring data then have to be processed locally for immediate or adaptive remedial actions and sent to some distant
maintenance or monitoring centers.
Finally, combining real-time information (sampled values,
generic object-oriented substation event messages, logical
information, and measurements) and monitoring data, a state
estimation of all the components of the substation may be
established and advanced automated area functions computed
(locally or remotely). For instance, the Poste intelligent will
enable a DLr calculation relying on weather-based information from all the surrounding lines. Furthermore, it will operate an adaptive and coordinated wide-area protection scheme.
in summary, a smart substation will be a mix of the following features (Figure 7):
✔ fully digitalized protection and automation system
✔ extensive monitoring system
✔ advanced functions implemented using local computing resources.
To achieve this target, a reliable and resilient telecommunication network between substations and control centers is necessary. Cybersecurity is also now a mandatory requirement.

Focus on a Fully Digitalized Protection
and Automation System
(a)

(b)

figure 6. The Blocaux (in Northern France) smart substation: (a) an old electromechanical and (b) a full digitalized
automation system. (Photo courtesy of RTE, used with
permission.)
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ieee power & energy magazine

in the switchyard, rTe has developed a structured substation architecture over the years, where all the protection
and automation functions necessary for the control of two
feeders were placed in one bay of the yard (including their
cubicles and auxiliary power supply). The main considerations for this placement were the voltage and power losses
on the copper cables and the reduction of electromagnetic
transient interference between the primary equipment and
the controls. For the past ten years, a fiber-optic ring or
star has linked each bay in the yard and bay control unit to
the main computers in the substation local control room,
where the remote terminal unit, sequence of event recorder,
disturbances recorders, human-machine interface (Hmi),
and administration console functions are located.
Digitalization technology was already available but only
partially implemented. over the past five years, the new
generation LPiTs, also called nonconventional instrument
transformers and the merging unit equipment, had reached a
technology readiness level. This encouraged us to try it in a
march/april 2018

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - March/April 2018