Synchronized Phasor Estimation Using Absolute Time Standard
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Solution Overview
Problem
Existing electrical power system monitoring and control technologies face challenges in achieving accurate synchronized phasor estimation due to time delays and the need for synchronized sampling frequencies across multiple locations, which affects real-time monitoring and control latency.
Innovation Solution
An apparatus and method that estimate synchronized phasors at predetermined times referenced to an absolute time standard, allowing for variable sampling intervals based on local power system frequency, eliminating the need for synchronized sampling frequencies and reducing time alignment requirements, thereby enabling quicker control actions and improved detection of power system anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synchronized sampling frequencies are used across multiple locations, then measurement synchronization accuracy is improved, but device complexity and time alignment requirements increase
Solution Approach 1:
The patent introduces an absolute time standard (such as GPS-based UTC) as an intermediary reference that all devices independently synchronize to. This mediator eliminates the need for direct mutual synchronization between devices, reducing complexity while maintaining measurement precision through a common time reference framework
Solution Approach 2:
The system performs preliminary time synchronization by establishing the absolute time standard before actual measurements are taken. Devices pre-synchronize their clocks to the absolute time standard, ensuring that when measurements occur, they are automatically aligned in time without requiring complex real-time coordination during the measurement process
2Adaptability or versatility
If fixed sampling intervals are used, then device complexity is reduced, but adaptability to varying power system frequency decreases
Solution Approach 1:
The patent implements dynamic sampling intervals that automatically adjust based on the detected power system frequency. Instead of using a fixed sampling rate, the system varies the sampling interval to match the actual frequency conditions, enabling adaptability while keeping the control logic relatively simple through frequency-dependent parameter adjustment
3Reliability
If state-estimation algorithms are used to monitor power system state, then comprehensive monitoring capability is improved, but control latency increases
Solution Approach 1:
The system performs preliminary computation of synchronized phasors at predetermined times referenced to the absolute time standard, rather than waiting for state-estimation algorithms to process measurements in real-time. This advance preparation of time-synchronized data reduces the computational delay and enables faster control responses while maintaining comprehensive monitoring through the phasor measurements
Data Source
AI summary
An apparatus and method estimates a plurality of synchronized phasors at predetermined times referenced to an absolute time standard in an electrical power system. The method includes acquiring and determining a frequency of a power system signal, sampling the power system signal at a sampling interval rate based on a frequency of the power system signal to form signal samples, and generating a plurality of acquisition time values based on an occurrence of each of the signal samples at a corresponding plurality of different times referenced to the absolute time standard. The method further includes adjusting a phasor of each of the signal samples based on a time difference between a corresponding selected acquisition time value and a predetermined time referenced to an absolute time standard to form the plurality of synchronized phasors.