ABB RELION 630 Series Product Manual page 12

Power Management
PML630/Compact Load-Shedding Solution
Product version: 1.2.1
ΣPower available from generators = ΣPower
actual generated + Σspinning reserve
ΣPower utility connection capacity = ΣPower
actually drawn from grid + Σadditional
drawing limit ( based on contractual
conditions )
ΣP
•
spinning reserve
of all the generators in the subnetwork. This
depends on the ambient temperature and
the capability of a generator and its working
mode. The generator (governor) working
mode and capability information can be
either set as parameters or acquired from an
external device or system over IEC 61850
GOOSE
ΣP
•
actual from generators
equal the load consumption in the
subnetwork.
ΣP
•
inhibited loads
consumption of the load feeders that do not
participate in the load-shedding due to
intended operator action or an automatic
system action or not configured for load-
shedding or an overall difference between
the power measurements from the sources
and the loads.
PML630's fast load-shedding function performs actions in the
power network cPMS load-shedding Configuration A.
• Builds subnetwork-wise dynamic load tables and power
network information for display in COM600S or COM600F.
PML630 identifies certain events as critical signals for initiating
the power balance calculation.
• Opening of a generator feeder or a grid transformer feeder
circuit breaker
• Opening of a bus coupler feeder or a tie line (network)
circuit breaker in its own power network area or from the
(remote-end tie feeder circuit breaker) adjacent power
network area.
• Protection lockout function operation of a critical circuit
breaker.
• Lockout function operation of a generator turbine.
• External input-based trigger that reflects an abnormal
situation like undervoltage condition. The external trigger
is effective only when there is power deficit in the
subnetwork like the other fast-load shed triggers.
The spinning reserve sharing during the power export
conditions at the grid 1 or grid 2 feeders can be based on the
criticality and the strength of the power network area to which
power is exported.
[1] Another alternative is the COM600's protocol gateway feature to access generator information from external systems.
12
is the total reserve capacity
[1]
.
ΣP
and
drawn from grid
is the total power
• If one power network area exports power to an adjacent
power network area, the load-shedding can be configured
to be done in the strong power network based on the
available power and thus continuing the power export.
• If the recipient power network area has sufficient
capability, the load-shedding can be configured to be
done in that power network area itself depending on the
available power.
Fast load-shedding for Configuration B
Coordination between peer PML630 devices
In Configuration B, the spinning reserve power sharing and the
load-shedding action information across the power network
areas are exchanged between the peer PML630 devices.
The spinning reserve power is always shared by the peer
PML630 devices with each other and their individual power
balance calculations always consider the spinning reserve
based on the tie line status across the power network areas.
The load-shedding action behavior can be automatically
handled by the PML630 device depending on the system
information or it can be parameterized depending on the
prevailing system conditions.
• The load-shedding sharing action behavior in a
Configuration B with two peer PML630 devices controlling
the adjacent (interconnected) power network areas is
automatically handled and the parametrized values are not
considered.
• If a load-shedding action completed by a PML630 device
in its area is inadequate (when more load relief is required),
it conveys the balance load-shedding information to the
adjacent area's PML630 device to shed the loads in its
power area based on assigned priorities.
• In a 3-peer PML630 Configuration B, the parametrization
is only effective for the PML630_2 as it is connected to the
two external network areas. The PML630_1 and
PML630_3 devices coordination occurs only with
PML630_2 device and it is handled automatically.
While the load-shedding action behavior of the PML630_1
and PML630_3 devices is identical to the 2-peer PML630
Configuration B situation, the PML630_2 can share its
balance load-shedding values information with its peer
PML630 devices. The sharing can be done on the 50-50%
or 0-100% or 100-0% basis. The PML630_1 and
PML630_3 initiate the shedding action in their respective
power network areas based on the sharing value
information. Sharing of load-shedding action is not
supported between PML630_1 and PML630_3.
Slow load-shedding
The slow load-shedding function reduces the overload on a
power source and reduces the power demand on the utility tie
1MRS757334 E
ABB