Closed‐loop control system for an improved hybrid flow controller and its comparison with some hybrid devices

Abstract

An improved configuration of the hybrid flow controller (HFC) is introduced to continuously adjust the power flow. In this configuration, a thyristor-controlled series capacitance (TCSC) is added to the conventional HFC to provide continuous variation in the HFC reactance. Moreover, simple closed-loop control methods are designed by considering all the practical constraints of TCSC for this improved HFC (IHFC) and another hybrid arrangement, which is called hybrid power flow controller. Furthermore, to compare and highlight features of the IHFC, simulation results of the designed controllers are carried out in different operating conditions and disturbances. This study also provides a quantitative comparison of various hybrid flexible AC transmission system devices.

A novel approach to multi‐objective optimisation of the size and location of an improved hybrid flow controller

“…Modelling of the IHFC P, Q, |V|, and the θ of the device's sending and receiving end buses are determined by power flow equations as follows [7]:…”

“…P , Q , | V |, and the θ of the device's sending and receiving end buses are determined by power flow equations as follows [7]: $$\begin{equation}{P}_{\rm{i}} = {P}_{\rm{j}}\ = \frac{{\left| {{V}_i} \right|\left| {{V}_{\rm{j}}} \right|\left( {\sin \left( {{{{\theta}}}_{\rm{i}} - {{{\theta}}}_{\rm{j}}} \right) + k\cos \left( {{{{\theta}}}_{\rm{i}} - {{{\theta}}}_{\rm{j}}} \right)} \right)}}{{{X}_{{\rm{ij}}}}}\end{equation}$$ $$\begin{equation}{Q}_{\rm{i}} = \frac{{{{\left| {{V}_{\rm{i}}} \right|}}^2\left( {1 + {k}^2} \right) + \left| {{V}_{\rm{i}}} \right|\left| {{V}_{\rm{j}}} \right|\left( {k\sin \left( {{{{\theta}}}_{\rm{i}} - {{{\theta}}}_{\rm{j}}} \right) - \cos \left( {{{{\theta}}}_{\rm{i}} - {{{\theta}}}_{\rm{j}}} \right)} \right)}}{{{X}_{{\rm{ij}}}}}\ \end{equation}$$ …”

“…Due to the discrete nature of an HFC unit, exact set points cannot be achieved. Therefore in order to overcome this drawback and to improve transient stability of the power system, a thyristor controlled series capacitor (TCSC) unit was included into HFC's structure [7] and improved hybrid flow controller (IHFC) was formed. IHFC can improve the transient behaviour of power system and continuously and precisely adjust the active power flow in the transmission lines.…”