Comprehensive online cable insulation monitoring
NSA3Smart Station Monitoring Unit
NSA3 is AOYI's in-house third-generation Smart Station Monitoring Unit. Beyond box transformer measurement and protection it integrates a communication gateway and fiber switch, and was among the first in the industry to bring cable sheath grounding current and cable-joint temperature into online monitoring. Widely used in solar, wind and energy-storage plants, it takes renewable sites a step closer to unattended operation.
A powerful central signal processing unit for the plant
Smart box transformer monitoring plus communication gateway functions
Self-healing fiber ring ports for unified collection and uplink of on-site signals
Solves data communication for electrical measurement and control systems in one place, with seamless connection to the grid dispatch system
Accurate cable grounding-current monitoring
- Wired online monitoring of changes and growth rate of cable sheath grounding current, with waveform and amplitude monitoring and alarms for sheath circulating current.
- Historical current is sampled and stored, insulation condition is assessed from the current trend, and over-limit grounding current triggers alarms.
Real-time cable-joint temperature monitoring
- Wireless online monitoring of cable-joint temperature and its trend.
- Sensor address, threshold, periodic reporting interval and over-temperature reporting interval are freely configurable.
- Over-temperature protection for each temperature sensor.
NSA3 Smart Station Monitoring Unit
Received the SNEC exhibition Highlight Award
Software copyright granted for the NSA-series Smart Station Monitoring Unit communication gateway software
NSA3 configuration table
Standard configuration, customizable per project
| Item | NSA3 |
|---|---|
| AC inputs | 3 groups |
| DC analog inputs (PT100 / 4–20 mA) | 6 total |
| Grounding-current input | 1 |
| DI (tele-signalling) | 40 |
| DO (remote control) | 10 |
| Item | NSA3 |
|---|---|
| Fiber ports | 2 |
| Ethernet ports | 4 |
| RS-485 master ports | 8 |
| 433 MHz wireless receiver | Yes |
| Protection | Electrical and non-electrical protection |
| Records | 500 |
NSA3 technical specifications
Type test passed: Tested by the National Quality Inspection and Testing Center for Power Transmission and Distribution Safety Control Equipment (State Grid Electric Power Research Institute) to DL/T 478-2013 and GB/T 7261-2016; all function, performance and EMC items compliant (report GJB23040115). PCCC product certified. Data per Technical Manual V2.0; configuration can be customized per project, with the contract technical agreement and drawings governing. Download manuals and protocols ›
AC analog inputs
- Current input
- 5 A or 1 A
- Voltage input
- AC 690V / 400V / 100V
- AC frequency
- 50 Hz or 60 Hz
- Current / voltage accuracy
- Class 0.5
- Frequency accuracy
- ±0.02Hz
- Power / power factor accuracy
- ±1%
Digital inputs / outputs
- Digital inputs
- AC/DC 220 V dry-contact inputs, opto-isolated with surge absorption, insulation withstand ≥ AC 1500 V
- Contact rating
- AC220V 8.0A；AC380V 1.9A；DC250V 1.5A
- Contact life
- > 100,000 operations
Communication
- Fiber ports
- ST connector, up to 50 km, forming a self-healing fiber ring
- Ethernet ports
- 10/100Base-TX
- RS-485 master ports
- Connects inverters, smart combiner boxes, multifunction meters, etc., with MODBUS-RTU to IEC 60870-5-103/104 protocol conversion
- Protocols
- MODBUS-RTU、IEC 60870-5-103/104、IEC 61850
- Wireless
- Wireless cable-joint temperature sensor access; optional wireless AP (password-protected, range approx. 100 m)
Protection and recording
- Non-electrical protection
- Light gas, heavy gas, transformer high / extra-high temperature, low oil level, pressure relief valve operation, etc.
- Electrical protection
- Overcurrent stages I/II/III, ground fault, overvoltage, undervoltage
- Records
- 10 pre-/post-fault waveforms, 500 SOE
Power supply
- Supply voltage
- AC/DC 220 V ±20%
- Supply frequency
- 50 Hz, −6% to +2%
- Rated power consumption
- ≤10W
Operating environment
- Operating temperature
- −40℃～+70℃
- Relative humidity
- Max. 90% monthly average RH in the wettest month, non-condensing
- Atmospheric pressure
- 80kPa～110kPa
- Site conditions
- No explosion hazard, conductive dust or corrosive substances
Mounting
- Mounting method
- Flush panel mounting, fixed by four holes on both sides of the front panel
- Depth
- 235 mm, plus ≥ 80 mm rear clearance for wiring
EMC
- Electrostatic discharge immunity
- GB/T 14598.14 (IEC 60255-22-2) Class III
- Oscillatory wave immunity
- GB/T 14598.13 (IEC 60255-22-1) Class III
- Radiated RF electromagnetic field immunity
- GB/T 14598.9 (IEC 60255-22-3) Class III
- Electrical fast transient / burst immunity
- GB/T 14598.10 (IEC 60255-22-4) Class A
- Surge immunity
- GB/T 14598.18 (IEC 60255-22-5) Class III
- Immunity to conducted disturbances induced by RF fields
- GB/T 14598.17 (IEC 60255-22-6) Class III
- Power-frequency immunity
- GB/T 14598.19 (IEC 60255-22-7) Class A
- Conducted and radiated emission limits
- GB/T 14598.16（IEC 60255-25）