Generator power transduction device and method

Abstract

The invention discloses a generator power transduction method. The generator power transduction method comprises the steps: firstly collecting generator terminal voltage transformer three-phase voltage, generator terminal measurement-level current transformer three-phase current and generator terminal protection-level current transformer three-phase current in real time, secondly respectively calculating fundamental wave phasors of the generator terminal voltage transformer three-phase voltage, the generator terminal measurement-level current transformer three-phase current and the generator terminal protection-level current transformer three-phase current, and calculating generator terminal protection-level current transformer three-phase current fault component, generator frequency, power 1, power 2 and power 3; utilizing current fault component criterion with a floating braking threshold feature; if the criterion is met, outputting the power 2; if the criterion is not met, identifying the criterion by utilizing frequency fluctuation; if the criterion function is inputted and the criterion is met, outputting the power 3; if the criterion function is not inputted and the criterion is not met, outputting the power 1. According to the generator power transduction method, the criterion false operation when a system generates frequency deviation or oscillation can be avoided, and active power is correctly outputted. The invention further discloses a generator power transduction device.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a generator power transmission device and a transmission method. Background technique [0002] The traditional generator power transmitter collects the generator terminal voltage and the current transformer current of the machine terminal measurement level, and uses the time division multiplier principle to generate an analog power signal, which is supplied to the distributed control system (DCS) of the unit and the digital electro-hydraulic control of the steam turbine. system (DEH) used. When a fault occurs outside the unit area or an adjacent transformer runs out, due to factors such as a large fault current or non-periodic components, the current waveform of the measuring-level current transformer at the generator end is distorted, resulting in the power transmitter being unable to be true. Reflect the current power of the generator and output wrong power, even make ...

AI Technical Summary

Problems solved by technology

When a fault occurs outside the unit area or an adjacent transformer runs out, due to factors such as a large fault current or non-periodic components, the current waveform of the measuring-level current transformer at the generator end is distorted, resulting in the power transmitter being unable to be true. Reflect the current power of the generator and output wrong power, even make DEH or DCS malfunction

According to on-site feedback, there have been many accidents in domestic thermal power units due to the output distortion of the power transmitter that caused the rapid control of the DEH valve to malfunction. In some cases, multiple units were shut down, and the consequences were quite serious.

[0003] Chinese patent application number 201410131932.X proposes a generator power transmission method based on the overcurrent fault identification criterion. This method uses the full-wave Fourier algorithm, and the implementation method is simple, but there are still some unresolved problems: (1 ) When a fault occurs in the light load condition of the generator, the sensitivity of the overcurrent fault identification criterion is not high

When a fault occurs under the light-load condition of the generator and the fault component contains a non-periodic component, because the fault current is not large, the current of the protection level current transformer is not greater than the threshold of the overcurrent setting value, and the power 2 (by The three-phase voltage of the machine-side voltage transformer and the three-phase current of the machine-side protection level current transformer are calculated) output, while the measurement level current transformer is saturated due to the influence of non-periodic component factors, resulting in current waveform distortion, and the final device outputs wrong power ; (2) When the system frequency shifts or the system oscillates, because the Fourier algorithm with a fixed sampling frequency cannot adapt to the large and rapid changes in the system frequency, the calculated value of the three-phase current of the protection level current transformer will appear sometimes When it is large or small, it is possible that the calculated value is greater than the threshold of the overcurrent setting value, resulting in wrong output of power 2

In addition, due to system frequency fluctuations, the positive-sequence voltage and positive-sequence current at the generator terminal calculated by the Fourier algorithm with a fixed sampling frequency are wrong values, so the calculated power is also a wrong value, resulting in the device outputting wrong power at this time

Images