Assessment of OLTC contributions to voltage controlled demand response using structural equation models

This paper proposes the use of structural equation modelling (SEM) to assess the contributions of on-load tap changer (OLTC) on voltage controlled demand response (VCDR) in future power systems. For the development of a VCDR scheme, optimal deployment of the available resources is necessary. Thus, understanding the contributions of voltage controlled devices such as OLTCs to VCDR will assist the optimal allocation of voltage resources. To illustrate the use of SEMs, simulations were carried out on the 9-Bus network. Further, we performed a comprehensive sensitivity analysis with respect to the frequency input gain of a modified OLTC controller. Generated data through sensitivity analysis was then analyzed using an SEM of the network in order to estimate the effect of each OLTC on VCDR. Also, this paper highlights the impact of load size, load-voltage dependency as well as transformer location on the ability of transformers to provide VCDR and in turn frequency control. Furthermore, the impact of the transformers on the steady state frequency was investigated.