Phase Detection in Polyphase Powerline Communication
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Solution Overview
Problem
In polyphase electric power supply systems, determining the phase connection of devices like electricity meters is challenging due to asynchronous powerline communications with respect to the alternating electrical signal, leading to complexity in network supervision and load balancing, and existing solutions either require synchronous frame transmissions or generate significant overhead.
Innovation Solution
A method where a transmitter device detects a zero-crossing of the alternating electrical signal, determines a time difference for data set transmission, and includes phase information in the data set if the difference is below a threshold, allowing the receiver device to determine its phase connection based on this information and the received data set, even with asynchronous communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronous frame transmission is used to determine phase, then measurement precision is improved, but device complexity increases and adaptability decreases
Solution Approach 1:
The patent changes the parameter of transmission timing from synchronous (forced zero-crossing alignment) to asynchronous (standard PLC timing), while compensating through timestamp-based phase calculation. This allows the system to use conventional asynchronous PLC communication without requiring specialized synchronous transmission hardware or protocols.
Solution Approach 2:
The patent introduces timestamps as an intermediary parameter that mediates between the asynchronous data transmission and the synchronous phase measurement requirement. The timestamp records the exact transmission time, allowing the receiver to calculate phase information without requiring the transmitted frame to be synchronized with the power line cycle.
2Measurement precision
If synchronous frame transmission is enforced, then measurement precision is improved, but adaptability to different communication standards decreases
Solution Approach 1:
The patent changes the parameter of transmission timing from synchronous to asynchronous, enabling compatibility with standard PLC communication protocols like G3-PLC and PRIME that use asynchronous transmission. The phase determination is achieved through timestamp analysis rather than forcing synchronous transmission.
3Measurement precision
If phase information is transmitted in every data set, then measurement precision is improved, but loss of energy increases due to overhead
Solution Approach 1:
The patent applies partial action by including phase information (timestamp data) only in necessary data sets rather than all transmissions. The receiver can determine phase from any data set that contains timestamp information, reducing the overhead compared to transmitting dedicated phase information in every frame.
4Adaptability or versatility
If asynchronous communication is used, then adaptability to PLC standards is improved, but measurement precision deteriorates
Solution Approach 1:
The patent introduces timestamps as an intermediary that bridges asynchronous communication and precise phase measurement. The timestamp records the exact transmission time, allowing the receiver to calculate the phase angle based on the time difference between zero-crossing detection and data reception, achieving high precision without synchronous transmission.
Solution Approach 2:
The patent replaces the mechanical/synchronous timing system with an electronic/software-based timestamp recording and calculation system. Instead of requiring hardware-synchronized transmission, the system uses software to record timestamps and compute phase information, achieving the same measurement precision through digital processing.
Data Source
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AI summary
In a polyphase electric power supply system via which powerline communication are setup between a transmitter and a receiver, the transmitter: detects a first zero-crossing of alternating electrical signal on a phase to which the transmitter is connected; determines a first instant at which the transmitter is expected to transmit a data set; determines a first time difference from said first zero-crossing and said first instant; includes in the data set information of the phase to which the transmitter is connected, when said first time difference is below a predefined threshold. The receiver: detects a second zero-crossing of the alternating electrical signal on the phase to which the receiver is connected; determines a second instant at which the receiver receives the data set; determines a second time difference from said second zero-crossing and said second instant; determines the phase to which the receiver is connected, from said second time difference and said information of the phase to which the transmitter is connected.