Voltage Divider Protective Arrangement for Low-Voltage Networks
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Solution Overview
Problem
Existing protective devices for high and medium-voltage networks are costly to adapt for use in low-voltage networks due to the need for primary voltage converters, which violate safety specifications when directly connected.
Innovation Solution
A protective arrangement using a voltage divider to safely connect the device to a low-voltage network, allowing direct connection without converters, with a series resistor forming part of the divider and integrated into a terminal for minimal space and cost, and compensating voltage reduction mathematically for accurate processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary voltage converter is used to connect the protective device to the low-voltage network, then safety specifications are met, but acquisition costs increase significantly
Solution Approach 1:
A voltage divider is introduced as an intermediary component between the low-voltage network and the protective device's voltage input. This voltage divider consists of a series resistor connected in series with the voltage input, creating a voltage division ratio that reduces the network voltage to a safe level for the protective device while avoiding the need for an expensive primary voltage converter.
Solution Approach 2:
The voltage divider changes the voltage parameter by creating a specific voltage division ratio. The series resistor is selected with a resistance value that, combined with the voltage input's input impedance, produces the required voltage reduction ratio to meet safety specifications while maintaining measurement accuracy.
2Ease of manufacture
If the voltage input is directly connected to the low-voltage network conductor, then acquisition costs are reduced, but safety specifications are violated
Solution Approach 1:
The voltage divider acts as a safe intermediary connection that allows direct mounting of the protective device to the low-voltage network without violating safety specifications. The series resistor in the voltage divider ensures that the voltage at the voltage input remains within safe limits even during transient overvoltages.
3Reliability
If a voltage divider is introduced to reduce voltage to safe levels, then safety is maintained, but device complexity increases
Solution Approach 1:
The voltage divider provides a simple intermediary solution that maintains safety without significantly increasing device complexity. The series resistor can be integrated into the terminal housing or mounted directly on the terminal, requiring minimal additional components and straightforward wiring connections.
4Area of stationary object
If the series resistor is integrated into the terminal, then space requirements are minimized, but manufacturing complexity increases
Solution Approach 1:
The series resistor is merged with the terminal housing or integrated directly into the terminal structure. This combining of components reduces the overall space requirements and simplifies assembly by eliminating separate mounting steps for the resistor, while the manufacturing complexity increase is offset by the simplified overall structure.
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
Enables cost-effective and safe connection of protective devices to low-voltage networks, maintaining safety and operational efficiency by ensuring voltage levels within design limits, allowing for comprehensive protection functions including over/undervoltage and directional overcurrent protection.
Implementation Method 1
the protective arrangement has a voltage divider via which the voltage input of the protective device is connected directly to a conductor of the electrical power supply network, the voltage divider being dimensioned such that the voltage present at the voltage input is within the design limits of the voltage input at all times
Data Source
Figure 1~2
AI summary
The invention relates to a protective arrangement (10) for monitoring an electrical power supply network (11) with a protective device (12), wherein the protective device (12) comprises at least one voltage input (14) for detecting a voltage signal by generating voltage measurements, and wherein the protective device (12) comprises a computing unit (18) which is configured to recognize, at least on the basis of the voltage measurements, a current operating state of the power supply network (11) and to generate an error signal if an impermissible operating state is present.