Datakom DPR-350 Network Analyzer and Protection Relay

Network analyser and directional overcurrent protection relay in 96×96 mm

The DPR-350 is a network analyser and directional protection relay in a standard 96×96 mm panel format with a low 53 mm depth. Datakom describes it as both a precise analyser (accurate MV power analyser, class 0.5%) and a protection relay with a 25 A current range, with dual current measurement circuits and protection curves selectable between IEC, ANSI, UK and US types, several of which can be enabled at the same time. A 128×64 pixel graphic screen shows multiple measurements, and through the RS-485 port the unit connects to SCADA and automation systems, while USB is used for parameter adjustment. It suits medium-voltage feeder panels and genset or transformer protection where space is tight. See our controllers and data acquisition category for related products.

Technical specifications

Standards printed on the datasheet: EN 60255 (electrical relays), EN 61010, EN 61326, EN 60068 and EN 60529, EU directives 2006/95/EC and 2004/108/EC, and UL 61010-1 3rd Edition with CAN/CSA-C22.2 (file E475547, volume D1).

Protection functions and communications

• ANSI 50/51 overcurrent, 46 negative-sequence overcurrent, 67 directional overcurrent, 50BF interrupter failure, 74 circuit connection monitoring, 79 reclosure and 94/69 MCB and contactor control.
• Protection curves: IEC Standard, Very and Extreme Inverse; UK Long Term Inverse; IEEE Medium, Very and Extreme Inverse; US Normal Inverse and Short Time Inverse.
• Analyser measurements: phase voltages, currents including neutral and ground, active, reactive and apparent power, power factor, frequency, negative and zero sequence currents and voltages, and T32Q value, plus four-quadrant energy counters.
• Other features: cold reclosure, two independent adjustment sets, self-test and internal failure monitoring, three-level password, manual and SCADA closing and opening, multiple languages and USB firmware upgrade.

Records are read through Modbus. The recording period is adjustable, and the 1 MB memory stores 35 event records and 15,000 periodic records.

Selection and installation notes

Check the supply first: the DPR-350 operates from 19-150 VDC, so it is intended for DC-supplied substation or genset panels rather than direct mains. Use 1 A or 5 A CT secondaries, and note that the current input can withstand 100 A AC for one second. Set up the unit through the free PC program over USB or RS-485, and keep the three-level password in mind when handing over to a client. The IP65 front rating requires the optional gasket. Because it contains protection functions, relay settings should be calculated and approved by the responsible protection engineer, and coordination with upstream devices must be verified before commissioning.

The user manual (72 pages) describes two levels of overcurrent configuration, so that level 1 can follow an inverse-time curve while level 2 acts as a definite-time short-circuit stage with an instantaneous trip when its timer is set to zero. Automatic reclosure (ANSI 79) allows up to four reclosure trials at different timers, with a configurable no-fault timer after which a reclosure counts as successful. Cold load pickup temporarily inhibits the protection thresholds when a feeder is re-energised after a long outage, so that high inrush does not cause a false trip. The analyzer and relay share the same unit, so one device can provide measurement for operators and breaker control for protection.

Selection and installation notes

A protection relay is selected from the functions the system needs, the CT and VT ratios and the trip outputs. Check the CT polarity and the direction of the power flow for directional functions, set the pick-up values and times from the protection study, test the relay by secondary injection and check the trip circuit before putting the plant in service. Settings are approved by the responsible protection engineer.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related Datakom products: Datakom DKM-409 Network Analyser with Scopemeter and Datakom DFC-0124 Reactive Power Controller.

Documents and quotation

The Datakom datasheet and user manual are provided for download. Send the supply voltage, CT ratios and quantity for a quotation; settings and approvals remain the responsibility of the project engineer.