Comparison of primary frequency control using two smart load types

Primary frequency control using smart loads with reactive only compensation (SLQ) has been shown in the past. In this paper, further improvement in frequency regulation is shown using smart loads with a back-to-back converter (SLBC) arrangement. This introduces additional flexibility and thereby, allows independent and wider control over active and reactive power consumption of the smart load. The improvement in frequency regulation with SLBCs is compared against SLQs through two separate case studies on 4-generator, 2-area test system and also the 39-bus New-England test system. A future scenario with reduced system inertia is considered for both case studies. Unlike previous exercises involving smart loads, in this study a detailed representation is used for both the multi-machine transmission system and the distribution networks down to the medium voltage (MV) level where the smart loads (SLBC/SLQ) are connected. This avoids the inaccuracies associated with load aggregation or use of system equivalents wherein the network constraints, spatial voltage variations etc. are not captured properly.