mittamuuntaja

Mittamuuntaja is a Finnish term that translates to "measuring transformer" or "instrument transformer" in English. It refers to a device used in electrical power systems to step down high voltage or high current to a level that is safe and practical for measuring instruments, relays, and control equipment. There are two main types of mittamuuntaja: voltage transformers (VTs) and current transformers (CTs).

Voltage transformers, also known as potential transformers (PTs), are designed to reproduce the voltage waveform of the primary circuit at a reduced scale. They typically have a primary winding connected in parallel with the high-voltage line and a secondary winding with a much larger number of turns. This ratio of turns allows for a proportional reduction in voltage.

Current transformers are designed to reproduce the current waveform of the primary circuit at a reduced scale. They have a primary winding, often just a single conductor passing through the transformer's core, connected in series with the line carrying the high current. The secondary winding has many turns and is connected to the measuring instruments or relays. The ratio of turns in a CT ensures that the secondary current is a safe and proportional fraction of the primary current.

Mittamuuntajat are essential for the safe and accurate operation of power grids. They allow for remote monitoring of system parameters, protection of equipment from overloads and faults through protective relays, and precise control of power flow. Without these devices, dealing with the high voltages and currents present in power systems would be extremely hazardous and impractical. They are a critical component in substations and power generation facilities worldwide.