Voltage data acquisition system PCS-221

for high-voltage measurementssimultaneous samplingfor fault detection

Product overview
Merging units sample AC analog values and transmit sampled values (SV) to protection relays, bay control units (BCU) or meters over optical channels using the IEC61850-9-2 protocol. They provide synchronized, high-resolution sampled data for digital substations and protection systems.

Functions

• IEC61850-9-2 sampled value transmission
• GOOSE transmission and reception
• GMRP support
• Voltage and current synchronization
• Reception of voltage sampled values from a busbar merging unit
• Voltage transfer
• Data synchronization

Features

• High-performance multi‑DSP hardware for high-speed, high-precision real-time data processing.
• Modular hardware design for straightforward upgrades and maintenance by qualified technicians.
• Optional function modules to meet varied application scenarios and user requirements.
• High-precision 16-bit A/D converters: two converters per AC sample channel; sampling rate of 80 samples per fundamental wave cycle. Real-time calculations complete within a single sampling period.
• Integrated HMI for status viewing and local interaction.
• Multiple time-synchronization methods supported: IEEE1588, PPS (pulse per second) and IRIG-B.
• Support for digital substation protocols including IEC61850-9-2LE and IEC61850-8 (GOOSE).
• Event recording: storage for the latest 128 binary bit-change reports and 128 device self-supervision reports.

Data synchronization

• When connected to multiple electronic and electromechanical CTs/VTs, input sampling signals (e.g. three-phase current and voltage) require synchronization across sampling modules.
• GPS PPS can gradually adjust sampling intervals across intelligent sampling modules via the merging unit to achieve automatic synchronous sampling; accuracy depends on GPS PPS integrity.
• Angle-adjustment interpolation provides synchronization without GPS dependence and can offer higher reliability; both methods may be combined for improved accuracy.

Connection to Protection & Control Devices
Merging units typically connect to protection and control devices over optical fiber using IEC61850-9-2. The protocol supports both Ethernet and point-to-point communication. Point-to-point links are used for devices with strict real-time sampling needs, while Ethernet is suitable for bay control units and metering devices with lower real-time constraints. Manchester coding is commonly used in point-to-point links.

Technical specifications

• Model type: PCS-221
• Protocol support: IEC61850-9-2, IEC61850-9-2LE, IEC61850-8 (GOOSE)
• Functions: Sampled value transmission, GOOSE TX/RX, GMRP, voltage/current synchronization, reception of voltage sampled values from busbar MU, voltage transfer, data synchronization
• Hardware: Multi‑DSP architecture
• A/D converter: High-precision 16-bit A/D, two converters per AC sample channel
• Sampling rate: 80 samples per fundamental wave cycle
• Real-time processing: Calculations completed within one sampling period
• Time synchronization: IEEE1588, PPS, IRIG-B
• Synchronization methods: GPS PPS and angle-adjustment interpolation (combinable)
• Event recording: 128 latest binary bit-change reports; 128 latest device self-supervision reports
• Design: Modular hardware with optional function modules
• User interface: HMI for status viewing