Final answer:
Transformers are used in power transmission lines to adjust voltage levels, stepping up the voltage for long-distance transmission and stepping down for consumer use.
Step-by-step explanation:
The device that cancels out some of the induced voltage in transmission lines is a transformer. Transformers are essential in the power distribution system because they can adjust voltage levels to suit different phases of transmission. Typically, electrical power is stepped up to very high voltages for long-distance transmission to minimize power loss. Before distributing the power to consumers, the voltage must be stepped down to safe, usable levels. This stepping down process is crucial to ensure that appliances receive the right voltage required for their operation.