Quick Answer
LTE450 is ideally suited to SCADA and industrial telemetry applications, replacing legacy UHF radio and satellite SCADA links with an IP-based cellular solution offering wider coverage, higher throughput, lower latency and lower operational costs. Common protocols including IEC 60870-5-104, DNP3 over IP, Modbus TCP and IEC 61850 MMS all operate transparently over LTE450.
SCADA Protocols Over LTE450
Modern SCADA protocols for utility applications are IP-based, designed to operate over any IP transport including cellular networks. The transition from legacy point-to-point radio SCADA (operating narrow-band UHF or VHF channels in the 150-470 MHz range) to LTE450 therefore does not require protocol changes at the SCADA application layer – the same SCADA master stations and RTUs can continue operating, with the LTE450 router simply replacing the legacy radio modem at each remote site.
IEC 60870-5-104 is the dominant protocol for European electricity utility SCADA, providing the TCP/IP transport encapsulation of the IEC 60870-5-101 SCADA information model. DNP3 over TCP/IP is widely used in North American and some UK utilities. Modbus TCP is common for simpler monitoring applications including water and gas infrastructure. IEC 61850 MMS (Manufacturing Message Specification) is used for substation automation, providing a richer information model aligned with the IEC 61850 data model for power system objects.
Latency Characterisation for SCADA
SCADA applications have specific latency requirements defined in IEC 60870-5 and NERC CIP standards. Class T1 (fastest) requires response within 100 ms for critical control commands; Class T2 requires 1,000 ms; Class T3 requires 10,000 ms for bulk data. On a well-engineered LTE450 network, typical round-trip latency for TCP-based SCADA applications is 40-120 ms, comfortably within Class T1 requirements and well within Class T2/T3. The main latency contributors in LTE are the radio scheduling delay (1-4 ms), HARQ retransmissions (variable), S1 transport delay (depends on backhaul), and EPC processing (5-20 ms).
Frequently Asked Questions
IEC 61850 GOOSE (Generic Object-Oriented Substation Event) messages are designed for high-speed protection communications with end-to-end latency requirements of 4-20 ms. Standard LTE450 can meet 20 ms (Class P2/P3) requirements with careful QoS configuration, but 4 ms (Class P1) requirements are generally not achievable over LTE. GOOSE is also a multicast protocol, which requires specific configuration in the LTE450 network to support. For protection relaying where GOOSE is required, the LTE450 network should be supplemented with fibre for the inter-relay communication paths where sub-5 ms latency is mandatory.
Legacy UHF SCADA radio systems (operating in the 150-470 MHz range, often at narrow channel bandwidths of 12.5 or 25 kHz) provide throughputs of 1.2-9.6 kbps per channel. LTE450 on a 5 MHz channel provides 15-30 Mbps shared capacity – three to four orders of magnitude more throughput. LTE450 also provides IP addressing of individual endpoints, routable to the corporate network; legacy SCADA radio uses proprietary addressing. The operational advantages of LTE450 (remote management, firmware updates, monitoring) over legacy radio are substantial.