Fault simulation in ultrahigh voltage substation

Ultrahigh voltage(UHV)and extra-high voltage(EHV)have been widely used in power system,so the requirement for technology of operation management,as well as the accident analysis and disposal are more pressing.Based on the theory of Newton-Laphson power flow method,this simulation system imitates the primary device and secondary circuit,together with the normal,the abnormal and accidents in operation.Through simulation in various situations,it validates that this design is capable of simulating the complicated faults in UHV and EHV accurately and in real time.In addition,it can analyse and dispose them efficiently.

Research and comprehensive evaluation on delivery schemes of the Grand Inga hydropower station

Congo River has abundant hydropower resources,and large-scale cascade power stations,such as the Grand Inga,can be constructed in downstream locations.However,the fragile economic foundations of the Democratic Republic of the Congo and neighbor!ng Central African countries,and the small-scale regional power consumption market prohibit the implementation of large-scale hydro power projects.As the high-voltage,I on g-dista nee power transmission tech no logy matures,hydropower from the Grand Inga can be delivered to load centers in other regions of Africa.This study establishes a 6 dime nsional comprehe nsive assessment model using the best-worst method to evaluate large-scale,I on g-distance,cross-border power intercon necti on projects.The model is applied to evaluate all the can didate in ter-regional power delivery schemes of the Inga III hydropower station,and the evaluation results can effectively help investment institutions and policy makers in policy making and potential market targeting.

Facile carbon cloth activation strategy to boost oxygen reduction reaction performance for flexible zinc-air battery application

Flexible and all-solid-state zinc-air batteries(ZABs)are highly useful and also in demand due to their theoretical high energy densities and special applications.The limitation in their performance arises due to their catalyst-coated cathode electrodes in terms of catalytic activity and stability as well as cost.In this paper,a novel and environmentally friendly activation strategy is developed to activate the carbon cloth(CC)for the electrodes.The activated CC serves as a catalyst-free air cathode with high conductivity,excellent mechanical strength,and flexibility,in addition to low cost.The strategy is performed by simply electro-oxidizing and electroreducing CC under ultrahigh direct current(DC)voltage in a diluted NH4Cl aqueous electrolyte.It is found that the electro-oxidation not only results in the formation of a graphene-like exfoliated carbon layer on the surface of CC but also induces the incorporation of oxygen-containing groups and doping of nitrogen and chloride atoms.After the electroreduction,theπ-conjugated carbon network of CC is partially restored,leading to the recovery of electroconductivity.Such an electroactivated CC shows excellent oxygen reduction reaction activity.The aqueous flexibility and all-solid-state ZABs are assembled using such an electroactivated CC cathode without any catalyst loading.Both ZABs can achieve good durability and deliver high peak power density and an energy density as high as 690 Wh kg^(−1),demonstrating the excellent potential of this electroactivated CC in practical devices.