Abstract:
The basic function of an electric power system is to satisfy the system load requirements
as economically as possible and with a reasonable assurance of continuity and quality.
Therefore, it is essential to maintain the reliability of the electric grid under all situations.
Reliability is a time varying function. It is the probability of a system performing its
purpose adequately for the period intended under the operating conditions encountered.
Under specified system conditions, how reliably power can be transferred from one
network zone to another through all the network transmission lines which interconnect the
electric systems is known as transfer capability. During any occurrence of uncertainties
such as: change in load, line impedances, voltage magnitudes, customer demands etc. in
the network, power transfer can’t be ceased, so to transfer power productively during these
unpredictable condition one needs to enumerate transmission reliability margin (TRM).
Available transfer capability (ATC) is the additional amount of power that may flow across
the interface. It can also become a useful indicator for the operator to indicate the amount
by which the inter area power transfers can be increased without jeopardizing system
security. To ensure effective power transfer over the transmission lines during the
occurrence of uncertainties an accurate estimation of TRM is required. In this work, a new
technique has been proposed for calculating TRM by using AC, DC, and DCQ load flow
method considering sensitivity to load, line admittances and voltage parameter. The TRM
estimation is incorporated with the ATC since when the amount of power transfer is
increased in the transmission network it needs to estimate that the system would be secured
under a reasonable range of uncertainty. The proposed technique is used for IEEE 6 bus
test system and is done for Normal distribution. The results are compared with previous
results for validation.
