DC Feeding Voltage Calculation Using Virtual Train Models
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Solution Overview
Problem
The challenge is to accurately calculate transmission voltage in a DC electrified railroad section while minimizing the number of sensors and sections, thereby reducing costs associated with increased sensor installations.
Innovation Solution
A DC-feeding-voltage calculating apparatus that uses model information and real-time data from both equipped and unequipped trains to estimate train operation information and calculate optimal substation voltage settings, allowing for effective utilization of regenerative power without the need for extensive sensor networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the traveling section of the train is divided into small sections to accurately estimate train position, then measurement precision is improved, but device complexity increases due to the increased number of current sensors and voltage sensors
Solution Approach 1:
The patent creates a virtual model (electrical characteristic value) that copies and represents the physical state of the train and overhead line system. Instead of using multiple physical sensors to directly measure train position, the system uses a single sensor to measure electrical characteristics (current, voltage) and then calculates position based on the relationship between electrical characteristics and train position. This virtual model approach reduces the number of physical sensors while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces electrical characteristic values as an intermediary between the physical train position and the measurement system. Rather than directly measuring train position with multiple sensors, the system measures electrical characteristics (which are easier to measure with fewer sensors) and uses these as intermediate data to infer train position. The electrical characteristic value acts as a mediator that connects the physical domain to the measurement domain with reduced sensor requirements.
2Measurement precision
If the number of current sensors and voltage sensors is increased to improve measurement accuracy, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent creates a virtual representation of the train's electrical state that copies the essential information needed for transmission voltage calculation. By using a single sensor to measure overhead line current and combining this with train operation information (power consumption, regenerative power), the system reconstructs the electrical characteristics without needing multiple physical sensors. This virtual copying approach maintains calculation accuracy while reducing sensor quantity.
Solution Approach 2:
The patent makes the single current sensor serve multiple functions: it measures overhead line current, provides data for calculating transmission voltage, and enables estimation of train position. Additionally, the system uses train operation information to simultaneously determine both power consumption and regenerative power states. This multi-functionality reduces the total number of sensors needed while maintaining measurement precision.
Data Source
AI summary
A DC-feeding-voltage calculating apparatus includes storage that stores train model information including information for controlling a regenerative power reducing amount in a train in an electrified section; feeding network model information including position information on a substation; and substation model information including control information on a substation voltage. On the basis of: the stored information; a voltage value, current values of feeders by train direction, the voltage and current values being measured in the substation; and first train information on a train including a wireless communication apparatus, an estimator estimates second train information on a train not including a wireless communication apparatus and outputs train operation information. A calculator, on the basis of the stored information and the train operation information, calculates a substation voltage setting value for controlling the substation voltage such that regenerative power is increased in a regenerative car in the electrified section.