ATC is the available transfer capability. In a solar study it is the
maximum power that can be injected into a substation without overloading
lines or causing voltage problems. In an area import power study such
as is used for RTS2, these are the transmission MW power import limits
for a wide range of outage contingencies. Of special importance are
auto transformer outages because of their rather long repair times.
LOLP is the loss of load probability at a point in time for a given
demand after variable resources have decreased the demand that ordinary
dispatchable generators serve. The LOLP is a lookup process of a COPT
capacity outage probability curve. The COPT is discussed in the RTS1
documentation.
LOLE is the loss of load expectation in days per year units in my programs.
The LOLE is the sum of daily LOLPs. It is identical to the Monte Carlo
counting of days per year there is loss of load. However the direct
COPT calculation is at least a million times faster than sequential
frequency and duration Monte Carlo when the accuracy is taken into account.
RTS is the IEEE reliability test system. Three IEEE RTS models were
developed by the IEEE RRPA committee by 1996. Of special interest are
the 1979 RTS model in which a 1986 paper calculated the exact indices
of this small 1979 model. In an effort to duplicate the 1986 paper
results the RTS1 program was realized. It is an exact indices calculator
duplicating the 1986 paper results exactly. However the RTS1 program
apparently has a more powerful indices calculator than was used in 1986
since the calculation process is not size limited but retains its exact
process accuracy for any system size since the numerical error in calculations
diminishes as each new generator is added to the COPT lookup table.
Once the RTS1 program was completed it became obvious to me that a 2 area
RTS program could be developed rather easily.
RTS1 is a single area reliability indices program. The input files are
Hdata and Gdata meaning hourly data and generation data. The program
has a unique feature in that you can ask it to seek a load level that
will give a specific LOLE value, usually 0.1 d/y for the US. But it
will find any LOLE value you wish to seek. The final convergence is
a newton convergence that gives up to six digits accuracy in the LOLE.
RTS2 is identical to RTS1 except it calculates the larger area 1 and a
smaller embedded area 2 each hour. The indices are compared and there is
a trick that is used to determine if an import transmission constraint
limits power into area 2 from the larger area 1 area. If so, the indices
note that the transmission constraint added a certain amount to the increase
in the indices of area 2 over area 1 and these are listed in the output.
The RTS2 program can automatically seek a certain load level that gives
a desired LOLE. Note that the LOLE being requested must not be lower than
the area 1 LOLE since it's not possible for area 2 to be more reliable than
area 1. A loss of load sharing for all the regions is assumed in the RTS 1
program and this is carried over to RTS2.