general, operating with
multiple distribution feeders interconnected under
normal conditions improves both reliability and
efficiency.
4. repurpose existing
AC infrastructure for MVDC distribution
networks, crucial select appropriate
DC voltage. However, this might cause power flow
to concentrate certain lines. Voltage choice can
significantly impact the size, cost and
complexity the converters and switchgear
used MVDC system, and the converter
topology, protection strategy and system
voltage need chosen together.6. While this involves higher cost,
it offers large advantages scalability and
stability.4 times the voltage
as DC, but the ageing and service life of
AC equipment with must also taken
into account, described the following
subsections.
In contrast, MVDC lines use converters, which
allow for flexible and precise power flow control.
4.
§ Economic feasibility.
§ infrastructure reuse. traditional
MVAC systems, single circuit consists three
conductors (or three conductors and neutral line)
for three-phase transmission. Even
if fault occurs, power can still supplied
through alternative routes, greatly enhancing
power supply reliability. Significant energy loss
can occur during voltage conversion, and if
the input output voltage level difference is
substantial, losses typically increase. Therefore, is
common practice MVAC systems implement
a radial configuration with tie switches normally
open; and, the event fault, isolate the
faulted section and close the tie switch restore
power adjacent sections. For example,
when replacing existing two-circuit overhead
MVAC network with MVDC system, the upper
conductor can assigned the positive (+) and
the lower conductor the negative (–).
§ Mesh configuration (including ring structure)
provides higher reliability, allows power
to supplied through multiple paths.3 Line configuration
MVDC systems have several unique characteristics
that oblige line configuration approached
differently from system.40
MVDC technologies and operational considerations
§ Conversion efficiency.
Depending the required level reliability of
the MVDC network, possible operate
with fully meshed interconnections adopt a
radial configuration when economic issues take
precedence:
§ Radial configuration offers ease management
and clear transmission path; the event a
fault, though, the entire power supply along the
affected route might interrupted. MVDC systems
the line configuration usually consists two
conductors and two conductors and a
neutral line.
§ Hybrid configuration: some cases, a
combination radial and mesh configurations
may used.
As shown Figure 4-7, the line configuration of
an MVDC line can categorized into asymmetric
monopole, symmetric monopole, and bipole types,
based converter topology, grounding scheme,
the number conductors, and other key factors.2 Network configuration and
reliability
Network configuration critical factor in
determining the reliability and operational efficiency
of power system.
Once the line configuration decided, and when
multiple circuits are used, the placement of
conductors must thought about. theory, possible apply
up approximately 1.
As result, multiple feeders can interconnected
and operated continuously.
.6. shown Figure 4-6,
MVDC systems can adopt variety network
configurations, each which affects the stability,
flexibility, and scalability the power system
