Plant connectivity study

A plant connectivity study contains a technical assessment of the possible connection of a plant according to the applicable Rules for Operating Distribution Systems (specifically, Annex 4) and it is often required by distribution system (DS) operators at their discretion.

The study is drawn up with regard to:

  • voltage conditions in all assessed nodes of the network,
  • load capacity of individual network elements,
  • adhering to the parameters of back effects on DS, i.e. in particular voltage variations caused by the continuous operation of the plant, voltage variations at switching, HDO signal attenuation, flicker, harmonics, and other criteria specified by the Rules for Operating Distribution Systems (depending on the character of the plant).

The distribution system operator will provide data for creating a connectivity study in the scope required for it to be drawn up.

The data usually include:

  • VHV or HV short-circuit output in the supply switchgear or the point from which the effect will be calculated,
  • existing and prospective values of load in the system,
  • related power supplies connected to the DS in its relevant part,
  • applicable requirements for connecting power supplies to the DS in its relevant part,
  • VHV/HV transformer parameters,
  • existing and prospective conditions of HDO,
  • line parameters to the point of connection – length, type, cross-section,
  • possible operating states (basic connection + connection during substitute supplies),
  • simplified map data.

Study scope

For power supplies connected to LV and HV networks, the scope is usually given by the station with the network supply transformer, the line with the assessed power supply and its recommended connecting point, and other lines with operated or planned power supplies and the loads of these lines. The operating states defined by the distribution system operator are assessed. Also, the study assesses possible overflows to higher voltage levels and their effect on the operation of the transformer voltage regulation.

The necessary calculations of the network run are performed using the PSSE programme (from Siemens) and, according to the distribution system operator’s requirements, they are performed for minimum summer loads, maximum winter loads or such loads at which maximum production in that network is reached.

The calculations are performed using the PSSE programme (from Siemens) on the basis of data obtained from the customer.

In terms of the company’s laboratory work and test engineering, there are several accredited workplaces providing a wide range of services. In the heavy current field, the HV/VHV test laboratory operates using a number of specified methods and tests which can also be applied to oils, the emissions and air pollutant measuring laboratories deal with air protection, the calibration laboratory for pressure and temperature deals with physical methods, while the fuel quality laboratory assesses fuels and their solid residues, including taking samples at a particular combustion or other source.

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