To connect a solar PV plant to distribution or transmission networks, it is necessary to step-up the voltage level from medium to high voltage, which usually means a substation. Substations are used to accommodate new energy generation, maintain reliability requirements to address congestion in the power grids, satisfy load growth and transmission capacity rapidly and break the power flow in scenarios of fault response.
As solar projects get larger, utility companies prefer to outsource the design of the substation. For this reason, RatedPower has launched a new feature to generate the basic engineering of some of the most common substations in pvDesign: line to transformer substation, single busbar substations and double busbar substations.
According to RatedPower’s data, 86% of pvDesign’s users prefer to automate the design of the electric substation of their projects. Of those users that choose to do so manually, 60% prefer a single busbar arrangement. On the other hand, 9.3% of the designs simulated in pvDesign preferred to connect to the network by a switching and breaking station. These stations would allow solar plants to be connected to networks whenever the output voltage is the same, for example in the case of medium voltage distribution networks.
In a fully automatic way, pvDesign carries out the basic engineering of the substation that best suits the photovoltaic plant. Its users only need to select the substation card and introduce the high voltage level. Only with this data, pvDesign is capable of generating in detail all the necessary documents of the step-up substation that will allow the connection of the photovoltaic plant to the distribution or transmission networks of the country.
On a study conducted by the Agency of the Cooperation of Energy Regulators (ACER), the number of transformer bays and the number of busbars are two of the most important factors when pricing a substation. This means that substations could represent between 5 to 10 percent of the total cost of a photovoltaic plant.
The calculation module of the step-up substation introduced in pvDesign allows in a very simple and fast way to obtain all the documents necessary for the design of the interconnection installation of the PV plant. The step-up substation or the breaking station are customized for each project. In other words, the plant’s medium voltage lines, the plant’s capacity and environmental conditions are taken into account.
Among the most important documents that pvDesign generates in seconds are:
1. Single line diagrams (SLDs) as a graphic representation of the electrical installation.
2. A design report that includes the descriptive memory of all the necessary equipment in the substation as well as safety distances, insulation coordination, values of short-circuit currents and characteristics of the busbar. Moreover, the design report includes the
descriptive memory of all the necessary equipment in the breaking station, such as feeder, auxiliary, protection and metering cubicles.
3. Profile, top views and general sections of the substation.
To sum up, RatedPower’s new feature will allow pvDesign users to design and engineer until the Grid Point expanding its software’s scope of work and improving the clients’ work experience and profitability.
— Solar Builder magazine