Jakeluverkon maakaapeloinnin vaikutukset käytöntuki- ja verkkotietojärjestelmiin

The tightening of requirements for the distribution networks’ quality of supply obliges distribution system operators to make large investments in distribution networks. Medium voltage network cabling is one prominent method to improve the reliability of delivery. However, the cable characteristics are different from the characteristics of an overhead line. An underground cable produces significant amount of both reactive power and earth fault current. In order to keep the touch voltages in acceptable limits during an earth fault, in addition to centralized coils also distributed arc suppression coils are being increasingly used. Transferring reactive power causes losses and major cost are caused by the Fingrid’s fee for inputting reactive power in main grid. The reactive power is being compensated by shunt reactors. The objective of this thesis was to find the development needs to ABB MicroSCADA Pro DMS600 software in the aspect of medium voltage network cabling. Representatives of 4 distribution system operators were interviewed and both measurements and simulations were performed to find the needs for improvements. Also the feasibility of active voltage level management feature Volt-VAr Control for Finnish customers was discussed. As an outcome of this thesis, several development needs were gathered. New devices such as shunt reactors and Dyn11+YN transformers need to be accurately modelled to enhance load flow calculation and to ease the network coding. The earth fault analysis method of present DMS600 version includes multiple simplifications that may cause inaccuracies in networks containing long cable feeders and multiple arc suppression coils. More accurate earth fault calculation method was presented to improve the accuracy of the earth fault analysis method. Needs for features and notices to support the distribution system operators in the planning and operation of distribution network consisting of distributed compensation coils were presented. For example visualizing the compensation degree of feeders could help the planning and operation of feeders containing distributed arc suppression coils. Also the analysing of multiple network plans that are in the area of same HV-MV substation should be possible. That way the growth of reactive power and earth fault current could be taken into consideration during network planning. Required theory and information for developing above mentioned improvements were gathered. However, future work is needed to implement features to the DMS600 software