![](bg5.png)
In Figure 5 we illustrate a situation where all the
model variables are set to their minimum value (0.1)
and achieve a maximum value of 0.9. It is also
assumed that the ideal operator applies correctly all
the domain concepts involved in the problem and
that the updating rate is constant.
It can be observed that, after the third iteration,
the concepts used in DS incident type overcome the
medium level (0.5), leading to a new type of incident
(DtR) in the next iteration. After the fourth iteration,
some concepts that are not used in DS but are
involved in DtR incident overtake the minimum
level for the first time.
We observed that an early introduction of new
concepts can contribute to increase the instructional
process efficiency. The problem selection
mechanism ensures that the problem sequence is not
monotonous, tending to stimulate the operator’s
performance with new kinds of incidents.
3 TUTORING MODULE FOR
RESTORATION TRAINING
3.1 Restoration Training Issues
The management of a power system involves several
distinct entities, responsible for different parts of the
network. The power system restoration needs a close
coordination between generation, transmission and
distribution personnel and their actions should be
based on a careful planning and guided by adequate
strategies (Sforna and Bertanza, 2002).
In the specific case of the Portuguese
transmission network, four main entities can be
identified: the National Dispatch Centre (CC); the
Operational Centre (CO); the Hydroelectric Control
Centres (CTCH); and the Distribution Dispatch
(EDIS).
The power restoration process is conducted by
these entities in such a way that the parts of the grid
they are responsible for will be slowly led to their
normal state, by performing the actions specified in
detailed operating procedures and fulfilling the
requirements defined in previously established
protocols. This process requires frequent negotiation
between entities, agreement on common goals, and
synchronization.
The purpose of the training tutor is to allow the
training of the established restoration procedures and
the drilling of some basic techniques. Power system
utilities have built detailed plans containing the
actions to execute and the procedures to follow in
case of incident. In the case of the Portuguese
network, there are specific plans for the system
restoration following several cases of sectorial
blackouts as well as national blackouts, with or
without loss of interconnection with the Spanish
network. Table 2 illustrates a service restoration
plan.
Table 2: Restoration Plan example.
Step
No.
PLAN STEP
0 Notify Distribution Dispatch Center about the
incident and expected restoration time. Wait for
150 kV to be available in SRA bus
1 Feed the 150kV to SRA bus using 400/150 kV
autotransformers
2 Switch SVI substation to manual
3 Energize the lines fed by the 150 kV bus of
SRA with priority to lines connected to
substations SOR and SRU and to power plants
CCD and CVN
4 Contact the Hydroelectric Power Plants’ CC,
asking for the restoration of their lines with
priority for the ones between CCD and CAR
and between CCD and SVI/CVF
5 Wait for the automatic operators of SCV and
SGR substations to restore the 150/60 kV
transformers, if no voltage is available in 60 kV
buses
6 Wait for SOR substation automatic operator to
restore the service, including the line to SVI
7 Finish the restoration of 150 kV line between
substations SRA and SED
8 Check if the automatic operators’ work is
concluded and finish the restoration if it has not
been done automatically
9 Notify Distribution Dispatch Center about the
end of the restoration process
Our Restoration training system use the concept
of agents (Jennings and Wooldridge, 1995), that can
be seen as virtual entities that possess knowledge
about the domain. As real operators, they have tasks
assigned to them, goals to be achieved and beliefs
about the network status and others agents’ activity.
They work asynchronously, performing their duties
simultaneously and synchronizing their activities
only when this need arises. Therefore, the system
needs a facilitator (simulator in Figure 2) that
supervises the process, ensuring that the simulation
is coherent and convincing.
In our system, the trainee can choose to play any
of the available roles, namely the CO and the CC
ones, leaving to the tutor the responsibility of
simulating the other participants.
AN INTELLIGENT TUTORING SYSTEM FOR OPERATORS’ TRAINING IN POWER SYSTEM CONTROL
CENTRES
41