Our electricity network supplies our customers with electricity and establishes the connection with the electricity-generating power plants at different voltage levels.
The electricity supply network generally includes four voltage levels. The primary extra-high-voltage network is usually designed for voltage between 220,000 and 400,000 volts (400 kV). 110 kV is common in a high-voltage network. Voltage levels between 1 and 36 kV are common in the downstream medium-voltage electricity network. The low-voltage level among consumers is operated with 400-volt three-phase alternating current and 230 volts for single-phase alternating current.
Three levels of transformation are added in addition to these four voltage levels. We obtain electricity from the inter-regional distribution network (level 3) at 60 kV and distribute the electricity throughout the coverage area via two substations and 100 transformer stations.
Electricity customers are connected to over 100 cable distribution cubicles and 100 transformer stations. Therefore, in terms of area, any maintenance and failure-related electricity interruptions can be kept to a minimum. The following table shows the specifications of the network infrastructure.
|Number of units||Plant||Nominal output||Voltage|
|1||Substation Islas||1 x 10 MVA - 1 x 15 MVA||60kV / 9kV (16kV)|
|1||Substation Bad||1 x 10 MVA - 1 x 20 MVA||60kV / 9kV (16kV)|
|104||Transformer stations||9kV (16kV) / 0.4kV|
|103||Distribution cubicles||0.4 kV|
St. Moritz Energie’s network obtains electricity from the feeds supplied by the higher-level network at the Islas substation and from the substation, Bad. During normal operation, the entire network can be switched to one or the other substation. This guarantees a large supply. In addition, part of the total energy supply is directly produced at the Islas power plant.