Phase Control Device Connection Error Detection
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Solution Overview
Problem
Existing phase control devices fail to accurately detect connection errors in three-phase voltage and current measurement wirings, leading to incorrect timing of circuit breaker operations, which can result in transient voltages and currents, and reduced lifespan of circuit breaker contacts.
Innovation Solution
A phase control device equipped with first to third voltage and current measurement terminals, a voltage measurement unit, a main circuit current measurement unit, and a connection error detection unit that includes phase sequence detection, collation, phase difference detection, and determination units to identify and correct connection errors, ensuring the circuit breaker operates at the target phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If connection error detection is performed using existing methods, then connection errors can be detected, but the detection is not accurate enough for three-phase voltage and current measurement wirings
Solution Approach 1:
The detection function is segmented into two independent units: a phase sequence detection unit that detects the phase sequence of voltage and current signals, and a phase difference detection unit that detects phase differences between corresponding phases. This segmentation allows each unit to focus on a specific aspect of connection error detection, improving overall accuracy while keeping each unit relatively simple.
Solution Approach 2:
The invention introduces an intermediary comparison mechanism that compares the detected phase sequence and phase difference against predetermined correct values. This intermediary comparison step acts as a mediator between raw signal detection and final error determination, enabling accurate detection without requiring complex analysis algorithms.
2Reliability
If accurate phase control is achieved through precise wiring connection, then circuit breaker operates at target phase, but wiring connection errors may occur leading to incorrect operation
Solution Approach 1:
The phase sequence detection unit and phase difference detection unit perform preliminary detection of wiring connection correctness before the circuit breaker operates. By detecting phase sequence and phase difference in advance, the system can identify connection errors before they cause incorrect breaker operation, preventing transient voltage and current issues.
Solution Approach 2:
The invention implements a feedback mechanism where the detected phase sequence and phase difference are compared with predetermined correct values, and the result is used to determine whether to proceed with circuit breaker operation. This feedback loop ensures that only correctly connected wirings result in breaker operation, eliminating the harmful effects of connection errors.
3Ease of manufacture
If simple and inexpensive detection configuration is used, then device cost is reduced, but detection capability may be insufficient
Solution Approach 1:
The invention extracts only the essential detection functions needed for connection error detection: phase sequence detection and phase difference detection. By taking out only these necessary functions and eliminating unnecessary complex analysis or additional sensors, the system achieves adequate detection precision with a simple and inexpensive configuration.
Solution Approach 2:
The invention uses basic, inexpensive detection components that perform specific single functions (phase sequence detection and phase difference detection) rather than requiring expensive multi-functional advanced sensors. These simple detection units are sufficient for the task and can be implemented with cost-effective hardware.
Data Source
AI summary
A phase control device includes a connection error detection unit. The connection error detection unit includes a phase sequence detection unit that detects a phase sequence of voltage signals, a phase sequence detection unit that detects a phase sequence of current signals, a collation unit that collates the phase sequence of the voltage signals and the phase sequence of the current signals and determines that a connection error is present when the phase sequences are different, phase difference detection units that detect a phase difference between the voltage signal and the current signal, and a phase difference determination unit that determines, when the phase differences output from the phase difference detection units fall without a determination range, that a connection error is present.