The effect of choosing a non-standard operating frequency on the equipment and infrastructure costs of an offshore AC network is investigated. The offshore AC network considered is similar in design to the European SuperGrid “SuperNode”. It is designed to connect several large wind arrays to multiple HVDC converters throughwhich power may be transmitted to shore. As the offshore AC network is i...

It is likely that any HVDC grids will evolve over time and will likely be multi-vendor and use several different technologies. This paper studies a four terminal network where the interconnecting link is operated as a normally open point. This allows the network to be reconfigured in the event of DC side fault, without the need for DC circuit breakers. The network uses the popular Modular Multi...

VFT (variable frequency transformer) has been recently used as an alternative to HVDC (high voltage direct current) to control power flow between asynchronous networks. VFT consumes less reactive power than a back-to-back HVDC system, provides faster initial transient recovery, and has better natural damping capability. VFT is simply a DFIM (doubly-fed induction machine) where the machine torqu...

Transient excitation boosting (TEB) has been installed on the Grand Coulee Third Power Plant hydrogenerators (three 600 MVA units and three 700 MVA units). TEB is initiated for outages of the 3100 MW Pacific HVDC Intertie, and results in a decaying pulse input to the gemrator voltage regulators. TEB temporarily raises Pacific Northwest transmission voltages which increases voltage-sensitive loa...

In order to improve the performance of voltage source converter-high voltage direct current (VSC-HVDC) system, we propose an improved auto-disturbance rejection control (ADRC) method based on least squares support vector machines (LSSVM) in the rectifier side. Firstly, we deduce the high frequency transient mathematical model of VSC-HVDC system. Then we investigate the ADRC and LSSVM principles...

Multirate simulation of electric networks exhibiting a wide variety of time constants decreases the simulation runtimes by exploiting the property of circuit latency. The fundamental idea is to use different integration steps for distinct elements and/or parts of the network according to requirements of accuracy for each element. HVDC converters are ideally suited for latency exploitation since...

Ester-based insulation fluids are being increasingly used in high-voltage insulation systems. The reasons are the advantages in the area of ecological compatibility and resource-saving provision. The intention to use ester-based insulation fluids in high voltage direct current (HVDC) equipment is new. The major challenge in designing the HVDC insulation system is, that the systems do not only e...