Voltage transformer secondary voltage drop tester and phase-angle difference testing method thereof

The invention discloses a voltage transformer secondary voltage drop tester and a phase-angle difference testing method thereof. The tester comprises a slave, a master and a GPS, wherein the slave is arranged at the output end of a voltage transformer to acquire the output voltage of the voltage transformer; the master is arranged on an energy meter side to acquire the voltage value of an energy meter connected with the output end of the voltage transformer; the GPS is linked with the slave and the master respectively to trigger the master and the slave to synchronously test the voltage at the energy meter end and the output end of the voltage transformer and transmits the tested data in a wireless mode to the master for processing to acquire the secondary voltage drop value of the voltage transformer; and the master and the slave comprise an analog signal acquisition circuit for acquiring electric signals respectively and are characterized in that the analog signal acquisition circuits are high-speed data acquisition units.