Rogowski Coil Busbar Temperature Estimation in Circuit Interrupters
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Solution Overview
Problem
Existing circuit interrupters face challenges in accurately measuring busbar temperature due to high voltage and limited internal space, making it difficult to implement effective temperature sensing systems.
Innovation Solution
A Rogowski coil is disposed around the busbar to sense current, and a test signal is injected to estimate temperature without a traditional temperature sensor, using high pass or band pass filter circuitry to separate current and temperature components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are used to measure busbar temperature, then temperature measurement capability is improved, but device complexity and design difficulty increase due to electrical isolation requirements, thermal constraints, and limited internal space
Solution Approach 1:
The patent extracts the temperature measurement function from the traditional temperature sensor and relocates it to the Rogowski coil, which is already present in the circuit breaker for current sensing. By utilizing the existing coil structure and its temperature-dependent electrical properties, the system eliminates the need for separate temperature sensors and their associated mounting, wiring, and isolation components.
Solution Approach 2:
The Rogowski coil serves dual functions: primary current sensing and temperature measurement. The coil's inductance and resistance characteristics change with temperature, allowing the same component to provide both electromagnetic sensing and thermal diagnostics without requiring additional hardware.
2Measurement precision
If traditional temperature sensors are installed on the busbar, then temperature sensing is enabled, but the limited internal space of the breaker is consumed and cable routing becomes constrained
Solution Approach 1:
The Rogowski coil serves dual functions: primary current sensing and temperature measurement. The coil's inductance and resistance characteristics change with temperature, allowing the same component to provide both electromagnetic sensing and thermal diagnostics without requiring additional hardware.
Solution Approach 2:
The patent extracts the temperature measurement function from the traditional temperature sensor and relocates it to the Rogowski coil, which is already present in the circuit breaker for current sensing. By utilizing the existing coil structure and its temperature-dependent electrical properties, the system eliminates the need for separate temperature sensors and their associated mounting, wiring, and isolation components.
3Measurement precision
If temperature sensors are used, then busbar temperature data is obtained, but electrical isolation requirements and high voltage constraints complicate the sensor design
Solution Approach 1:
The patent extracts the temperature measurement function from the traditional temperature sensor and relocates it to the Rogowski coil, which is already present in the circuit breaker for current sensing. By utilizing the existing coil structure and its temperature-dependent electrical properties, the system eliminates the need for separate temperature sensors and their associated mounting, wiring, and isolation components.
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
This method allows for accurate temperature estimation of the busbar, enabling fault detection and preventing overheating issues without the need for additional sensors, thus improving diagnostic capabilities and operational safety.
Implementation Method 1
a Rogowski coil disposed around the busbar and structured to sense current having a first frequency flowing through the busbar
Implementation Method 2
high pass or band pass filter circuitry structured to receive an output of the Rogowski coil, the output including a first component having the first frequency and being proportional to the current flowing through the busbar and a second component having the second frequency and being proportional to a temperature of the Rogowski coil, and to attenuate the first component of the output of the Rogowski coil
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A circuit interrupter including a busbar, a Rogowski coil disposed around the busbar and structured to sense current having a first frequency flowing through the busbar, a test injector circuit structured to input a test signal having a second frequency to the Rogowski coil, high or band pass filter circuitry structured to receive an output of the Rogowski coil, the output including a first component having the first frequency and being proportional to the current through the busbar and a second component having the second frequency and being proportional to a temperature of the Rogowski coil, and to attenuate the first component of the Rogowski coil output, and an electronic trip unit including a temperature measurement unit structured to receive an output of the high or band pass filter circuitry and to estimate the temperature of the busbar based on the output of the high or band pass filter circuitry.