Servo Switch Assembly with Dual Position Feedback Safety Control
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Solution Overview
Problem
Existing switch assemblies in substations, such as on-load tap-changers and circuit breakers, face challenges in ensuring operational reliability due to potential malfunctions during operation, which can have severe technical and economic consequences.
Innovation Solution
A switch assembly with a servo drive system that includes a motor, power section, feedback system, and programmable safety controller, which determines the absolute position of the drive shaft using multiple methods to generate feedback signals, allowing for controlled operation and initiation of safety measures in case of safety-relevant events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single feedback system is used to determine drive shaft position, then device complexity is reduced, but reliability decreases due to potential incorrect position determination
Solution Approach 1:
The patent applies local quality by using two different feedback systems with different measurement principles (e.g., absolute encoder and incremental encoder) to determine the position of the drive shaft. Each feedback system has its own local measurement capability, and their results are evaluated independently and compared by the control unit to detect inconsistencies and initiate safety measures, thereby improving reliability without requiring a completely redundant dual-system architecture.
2Reliability
If multiple feedback systems are implemented to determine drive shaft position, then reliability increases, but device complexity increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the position values from two different feedback systems and comparing them in real-time. The control unit evaluates whether the values agree within a predefined tolerance range, and if not, automatically initiates safety measures. This feedback mechanism enables the system to self-diagnose and respond to inconsistencies, improving position determination reliability while keeping the control logic manageable through rule-based comparison.
3Reliability
If safety measures are automatically initiated upon detecting inconsistencies, then operational safety is improved, but productivity decreases due to potential unnecessary shutdowns
Solution Approach 1:
The patent applies preliminary action by pre-defining tolerance ranges and evaluation criteria for comparing feedback values before actual operation. The control unit is pre-programmed with safety rules and response protocols, allowing it to quickly evaluate inconsistencies and make immediate safety decisions without complex real-time analysis. This preliminary preparation enables rapid safety responses while minimizing unnecessary shutdowns through pre-established decision thresholds.
Data Source
AI summary
A switch assembly includes a switch and a servo drive system. The drive system includes: a drive shaft connecting the drive system to the switch; a motor driving the switch; a power section supplying power to the motor; a feedback system; and a programmable safety controller. The feedback system determines at least two values for an absolute position of the drive shaft; and generates a feedback signal on the basis of the values. The controller controls the power section depending on at least one desired value; influences an operation of the motor depending on the feedback signal; and identifies the presence of at least one safety-relevant event, and based thereon, transmits a control signal to the power section. The power section is initiates/carries-out at a safety measure depending on the control signal.