Smart Grid Technology in MV/LV Substations
This smart grid application involves the utilization of flexible LEM ART Rogowski coil sensors in conjunction with a smart meter connected to the low-voltage (LV) side of a distribution transformer within an MV/LV substation.
The software embedded in the smart meter performs calculations based on the LV measurements, enabling the determination of many indicators useful to identify the status of the electrical system, including oil temperature, ageing rate, current values, and power flow.
Advantages for Distribution System Operators
- Real-time monitoring of electrical parameters
- Creation of LV load curves for consumers, producers, and transformers
- Detection of unexpected losses and efficiency improvement
- Aggregation of active energy distributed by each MV-LV transformer
- Detection of non-technical issues on the MV side
- Overall accuracy better than 1% — exceeding conventional CTs
IoT Remote Energy Monitoring for the Smart Grid
The Internet-of-Things (IoT) is exceptionally well-suited for the implementation of smart grids, primarily due to the extensive range requirements and the minimal data size required for transmission. Leveraging narrow-band RF — the standard for long-range communication — enables the development of an innovative remote energy monitoring solution.
IoT Solution Architecture
This solution involves deploying wireless energy meters for remote monitoring of electrical equipment, incorporating:
- Hardware with ATO (A) or ART (B) sensors
- M2M connectivity (LORA, SIGFOX, 3G/GPRS)
- Web services for data management (history, alerts, graphs, statistics)
Each wireless energy meter connects to the RF long-range internet and transmits maintenance data to a secure web server. End-users can remotely monitor equipment usage and receive alerts for anomalies such as power loss or power peaks.
Key Advantages of IoT-Based Monitoring
- No need for deploying local network infrastructure
- Monitoring of both outdoor and indoor equipment
- Wide area coverage with very low energy consumption
- Long-lasting autonomous energy meters
- Affordability and easy deployment with LEM ATO or ART sensors
Smart Grid Solutions on Distribution Overhead Line Monitoring
New line current sensors enable utilities to monitor overhead distribution lines, maximizing their capacity and preventing clearance violations to enhance the reliability and efficiency of the MV Distribution Grid.
The monitoring of overhead power lines has become faster, easier, and more cost-effective with the advent of new IoT telecom networks such as NB-IoT and LPWAN. Utilizing a line sensor installed between two MV poles, grid operators can visualize real-time current flow, optimizing power line capacity for improved electricity distribution.
Line Sensor Benefits
- Designed for 1–35 kV distribution grids
- Periodic time-synchronized measurements
- Conductor surface temperature monitoring
- Fault condition detection and notification
- Real-time equalization among different lines in meshed networks
- Uses LEM ART split-core Rogowski coil for AC measurement
Smart Grid Product Portfolio
| Product | Technology | Current Range | Bandwidth | Accuracy |
|---|---|---|---|---|
| AHR | Open Loop Hall | 2000–3000 A | 20Hz–6kHz | 1% |
| AI-P1A | Integrator | 5000 A | 1500 Hz | 0.5% |
| AI-PMUL | Integrator | 5000 A | 1500 Hz | 0.5% |
| AK | Current Transformer | 5–400 A | 20–100 Hz | 1% |
| AKR | Current Transformer | 5–2375 A | 10–400 Hz | 1% |
| AP | Prime Air-Core | 50–400 A | 30–2000 Hz | 1% |
| APR | Prime Air-Core | 50–400 A | 30–6000 Hz | 1% |
| ART | Rogowski Coil | — | 300–420 kHz | 0.5% |
| ARU | Rogowski Coil | — | 320 kHz | 0.5% |
| ARH | Rogowski Coil | — | 462 kHz | 0.5% |
