On image transformation for partial discharge source identification in vehicle cable terminals of high-speed trains

Partial discharge(PD)detection of cable terminals is crucial for the safe operation of the traction power system in trains.However,similar PD signals in complex train-operating environments cause difficulty to recognise the insulation defects.Therefore,a PD signal image transformation recognition method is proposed for PD detection of cable terminal defects to identify defects in cable terminals with similar PD characteristics accurately.In the proposed method,the raw PD signals are firstly transformed to images via the Gramian angular field(GAF)representation.This can reveal the discriminative characteristics embedded in the original PD signals and subsequently facilitate differentiating the PD sources,which exhibit similar characteristic in the time domain.The obtained GAF representation of PD signals(named as PD GAF images)is extracted from local and global features to train an efficient MobileVIT model,which is then utilised to identify similar types of PD sources in cable terminals.The results show that the proposed method achieves 97.5%recognition accuracy in the field experiment,which is superior to other methods.

Organic Fuel Synthesis from Atmospheric Carbon Dioxide and Hydrogen Produced from Water by Electrolysis

Synthesis of organic fuels from carbon dioxide and hydrogen is analysed,in terms of energy recovery efficiency,and the required energy input for electrolysis of water.This electrical energy is related to the thermal energy required in a power station.A method is described to recover heat from energy-producing reactions in the fuel synthesis process,which can then be used to reduce the electrical energy requirement for electrolysis.By co-locating the fuel synthesis plant with a thermal power station,primary(thermal) energy can be used to produce high temperature steam,with a lower electrical requirement for electrolytic production of hydrogen.This can make more efficient use of the primary energy than a thermodynamic engine.Comparison is made with alternative fuels,in terms of energy budget,sustainability,carbon dioxide emissions,etc.The energy security benefits of advanced fuel synthesis are also identified.

Review of System Strength and Inertia Requirements for the National Electricity Market of Australia

Synchronous generators(SGs)are still making major contributions to the re-stabilization of a power system following voltage/frequency disturbances,attributed to their inherent capability of providing system strength and inertia.However,SGs powered by fossil fuels are operating to a lesser extent and scheduled for decommissioning in the National Electricity Market(NEM)of Australia due to the accelerating increase of low bidding priced asynchronous generation of wind and solar,which leads to the reduction and even in some cases,a shortage of system strength and inertia.This paper comprehensively reviews the requirements of system strength and inertia in the NEM from an operational security perspective.Australia is the first country that established the regulation rules of system strength and inertia to accommodate issues of an emerging high penetration level of non-synchronous renewable generation.