An electric meter measures the amount of electric energy consumed by residential, commercial, or industrial customers. Currently, smart meters are primarily used for billing purposes. However, advanced electric meter technology could enable accurate monitoring and control of voltage stability. Voltage stability could be mitigated at the end user level if every end user has sufficient real and reactive power control. There is a downside to this approach since load can have very diverse behaviors at the building level as opposed to at the bulk power system where loads are studied in aggregation. Such diversity poses challenges to voltage stability monitoring. The voltage stability monitoring algorithms designed for transmission systems cannot be directly applied to the smart meter data. The major challenges with current smart meters are the low time accuracy and low sampling rate. In the U.S., most smart meters select a real-time clock (RTC) as a timing source to report customer energy demand (kW) and consumption (kWh) at time intervals on the order of tens of minutes. For power providers, these time intervals are too large and may lead to monitoring failure for grid events, especially the grid transient event.
LLNL inventors have developed a smart meter device which consists of three functions: a machine learning based critical voltage characteristics detection algorithm, a real-time voltage stability monitoring algorithm using smart meter measurements, and a control algorithm that proactively sends signal to house/building controllable loads and distributed energy resources to request reactive power support or reduce real power consumption. Furthermore, there is the option to include chip-scale atomic clocks and GPS to perform independent stable time synchronization which adopts a compact design that can simplify installation and maintenance on the smart meter device. This innovation accurately synchronizes an atomic clock or GPS timing system to events recorded by the smart meter.
The smart meter device:
- enables real-time voltage stability margin estimation
- conducts real and reactive power control at an individual phase of an individual house or building.
- enhances existing smart meter technology with voltage stability monitoring which enabling more granular active/reactive power control at an individual building level.
The compact, modular chip-scale atomic clock (CSAC) enabled synchro electricity meter option (Patent No. 11,496,143) can perform fast and flexible time-synchronized measurements at the consumer end. This allows for measurement of consumer behavior with time synchronization and fixable sampling frequency greatly enhancing the quality and capability of smart meter data. The CSAC can provide pulse per second (PPS) signals independently with high-precision and high-stability.
- Improvement of system-level load data usability. With the time tag from CSAC or GPS, the metering data obtained from different locations can be efficiently synchronized and sorted for system-level studies.
- Time-synchronized smart meter data can be used for advanced data analytics and machine learning applications.
Almost half of all U.S. electricity customer accounts have smart meters, where 70.8 million advanced metering infrastructure (AMI) were installed by 2016 and 88% of the AMI installations were residential customer installations. Those smart meters have a general life span of 10 to 15 years. Thus, there currently is a big market for the next-generation of smart meters.
In addition, under California law new homes must come with solar panels, thus a requirement for high resolution is on the horizon. With 4-quadrant smart inverter control, the distributed energy resources (DERs) such as photovoltaics (PVs) which have both real/reactive controllability may help mitigate voltage stability in a more efficient and prompt manner. The proposed new smart meter is designed with advanced functionalities and upgraded performances. It can help utilities and customers address lots of technical problems. Ability to coordinate time synchronized smart meter (SSM) with Seismometer. PG&E has lead a SmartMeter and Seismometer project to identify the relationship between electricity delivery and ground motions under earthquakes. The proposed SSM can provide high-speed, high-accuracy, time-synchronized measurement at customer end.