Protective Relay Detachable HMI Segmentation
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Solution Overview
Problem
Existing protective relays in power distribution systems lack flexibility in parameter settings and may not be suitable for applications where auxiliary power supply is not feasible, particularly in urban Ring Main Units (RMU) installations.
Innovation Solution
A digital protective relay with a base Human Machine Interface (HMI) using DIP switches and an optional detachable HMI with advanced input means, such as a numerical keyboard or touch screen, allowing coarse and fine tuning of operating parameters, and a self-powered design using current sensing transformers, with an optional backup power supply for continued operation during power line shutdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a protective relay uses a fixed HMI with basic input means, then the device complexity is reduced, but the adaptability and ease of operation are limited
Solution Approach 1:
The HMI is divided into a fixed base unit and a removable extension module. The base unit contains essential components, while the extension module provides additional input means (numerical keyboard, touch screen) that can be attached or removed based on operational needs, thereby increasing adaptability without permanently increasing device complexity.
Solution Approach 2:
The HMI configuration is made dynamic through the removable extension module that can be added or removed to change the input capabilities. This allows the system to adapt its interface complexity to match the specific operational requirements, providing both simplicity and advanced functionality as needed.
2Ease of operation
If a protective relay uses a removable HMI module, then the ease of operation and adaptability are improved, but the device complexity increases
Solution Approach 1:
The HMI is segmented into a fixed base unit and a removable extension module. The extension module contains advanced input means that enhance ease of operation when needed, while the base unit remains simple for basic operations, balancing usability with manageable complexity.
Solution Approach 2:
The removable extension module serves multiple functions by providing both advanced input methods (numerical keyboard, touch screen) and serving as a protective cover for the base HMI. This multi-functionality justifies the added complexity by delivering tangible operational benefits.
3Adaptability or versatility
If a protective relay is designed as self-powered using current sensing transformers, then the adaptability to power-constrained environments is improved, but the reliability may be compromised during power line shutdowns
Solution Approach 1:
A backup power supply (battery or capacitor) is integrated into the protective relay to provide energy storage in advance. This backup power ensures continued operation of the microcontroller and data recording functions during power line shutdowns or transient failures, thereby maintaining reliability while preserving the self-powered design's adaptability to power-constrained environments.
4Ease of manufacture
If a protective relay uses mechanical DIP switches for parameter setting, then the ease of manufacture and robustness are improved, but the ease of operation and adaptability are reduced
Solution Approach 1:
The parameter setting interface is segmented between mechanical DIP switches in the fixed base HMI and advanced input means (numerical keyboard, touch screen) in the removable extension module. This segmentation allows the base unit to remain simple and easy to manufacture, while the optional extension provides enhanced ease of operation for complex parameter settings.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances flexibility and usability by enabling users to adapt parameter settings according to evolving needs, provides non-fading feedback, and ensures continued operation for recording pre-fault data even after power line shutdown.
Implementation Method 1
the energy required by the relay electronics circuit as well as the energy released to the trip coil is supplied by current sensing transformers
Implementation Method 2
an auxiliary or backup power supply such as a battery or capacitor
Data Source
Figure 1~2
AI summary
The present invention is concerned with a fully operational digital protective relay or Intelligent Electronic Device (IED) for protecting electrical equipment of a power distribution system. The relay comprises an input module, a processing module and an output module. Signals received from current transformers connected to the input module are evaluated by the processing module, and in reaction there to, trip signals may be output to an actuator of a circuit breaker via the output module. A base Human Machine Interface (HMI) enables a user to enter operating parameters such as delay time or nominal current to the processing module. As an option, a further HMI may be attached to the protective relay and connected, via a suitable interface for data exchange, to the processing module for the purpose of displaying protection-related information to a user. This further HMI is both optional and detachable, i.e. it may be repeatedly attached to and detached from the protection device. The detachable HMI provides for an increased flexibility in the use of the protective relay, as a user may adapt its interfacing capability by acquiring a detachable HMI of the type and at the time that suit best his evolving needs.