Large-scale power rectifier cabinet silicon controlled rectifier continuity detection device

Abstract

A high-power silicon controlled rectifier cabinet continuity detection device comprises three parts, namely a signal acquisition part, a signal processing part and a transmitting and displaying part, wherein the signal acquisition part acquires the bridge arm current of a silicon controlled rectifier via a sensor and measures the tube voltage drop of the silicon controlled rectifier via a low time-lag transmitter. As the bridge arm current and the tube voltage drop of the silicon controlled rectifier are opposite in phase, when the silicon controlled rectifier is cut off, the tube voltage drop is the anode alternating current line voltage; when the silicon controlled rectifier is triggered to be on, the tube voltage drop is very low as 2V approximately; each round comprises a continuity period and a cutoff period; and according to the relationship, the signal processing part can preliminarily judge whether the silicon controlled rectifier is in a controllable state.

Description

technical field [0001] The invention relates to a power rectifier cabinet for the excitation system of a medium-to-large or giant generating set, in particular to an occasion where the excitation current is large and multiple rectifier cabinets need to be connected in parallel. Background technique [0002] In the generator excitation system, the power rectifier converts AC power into DC power and provides excitation current for the generator excitation winding. It is the output part of the excitation system and the foundation of excitation. The core of its work, the reliability of its work is beyond doubt. Due to the harsh actual working condition of the thyristor, large current, large heat generation, and high commutation voltage, there are many difficulties in real-time detection of its operating status. At present, the conventional design of power rectifier cabinets adopts the installation of fast fuses and output The single-cabinet ammeter signal is given to the user i...

AI Technical Summary

Problems solved by technology

Due to the harsh actual working condition of the thyristor, large current, large heat generation, and high commutation voltage, there are many difficulties in real-time detection of its operating status. At present, the conventional design of power rectifier cabinets adopts the installation of fast fuses and output Single-cabinet ammeter signal to the user in order to judge the working condition of the silicon controlled rectifier

The fast fuse is installed in series in each thyristor branch. When the thyristor short-circuits, the fast fuse exits the branch and sends a corresponding alarm signal to the user. This design can respond to a certain extent. The extreme working condition of the thyristor short circuit, but for the thyristor open circuit or the non-triggering or false triggering caused by the fault of the control circuit, it cannot be correctly judged

As for the ammeters sent to users, the criteria are rough. Even if the fault of the rectifier cabinet can be judged according to the large deviation of the current, the fault branch cannot be accurately located; In most cases, multiple thyristor rectifier cabinets need to run in parallel. If a branch fails, the current deviation will not be very large, which may cause users to relax their vigilance and cause hidden dangers.

As the capacity of the unit increases, the requirements for the excitation system and the rectifier cabinet of the excitation system are becoming increasingly strict. Insufficient detection of power components in rectifier cabinet design

Images