Video: Nexus 1500 – Product

Video transcript

What the Nexus 1500+ plus measures, why its accuracy holds over the years, and what it records when the network misbehaves. At a substation or a large supply point, the same connection has to answer 3 questions: how much energy went through, whether the voltage met the standard, and what exactly happened during a dip or a fault. The Nexus 1500+ plus answers all 3 from one set of instrument transformers. Four figures sum it up:

0.06% energy accuracy, class A power quality to IEC 61000-4-30, transients at 50 megahertz, and waveforms at up to 1024 samples per cycle. Every 10 seconds a separate circuit checks the input signal and corrects the metrology, so accuracy holds with time and temperature. Readings exceed class 0.1 of ANSIC 12 point 20, typical accuracy as shipped is 0.02%, and two test pulses on the front let you verify it. As a revenue meter it measures in 4 quadrants, with a practically unlimited history. It compensates transformer and line losses and the errors of the C Ts and P Ts,

adds gas or water meters through pulse inputs, and handles tariffs with a perpetual time-of-use calendar. Harmonics, flicker, unbalance, dips, swells and interruptions are measured to class A, so two class A instruments give comparable results. Harmonics go up to order 511, EN 50160 reports are produced automatically, and every voltage event is plotted on the CBEMA curve. Two recorders work side by side. One captures voltage and current waveforms,

with the cycles before and after the event and faults up to 8 times full scale. The other samples transients at 50 megahertz, to see what happens inside a single cycle. Records export to COMTRADE and PQDIF. The phasor measurement unit time-stamps every voltage and current phasor against GPS time, and sends synchrophasors to a phasor data concentrator. With meters in several substations on the same time base, the operator sees the whole area at once, and can detect islanding.

Six ports work at the same time: two Ethernet ports with separate addresses, one of them in fibre, two optional RS-485 ports, and USB and optical on the front. Modbus, DNP3 and IEC 61850 run in parallel, so billing, SCADA and engineering each have their own path. Functions come as upgrade keys, activated in the field. V1 is the base. V2 adds memory, resolution and IEC 61850. V3 adds the 50 megahertz transient recorder.

And V4, V5 and V6 add the phasor unit and the security package to each of the first 3. Communication is encrypted, passwords are complex and expire, failed attempts lock access for a while, and roles define what each user may do. The firmware is signed, and a log records every change made to the meter. Its place is wherever a small error turns into a large cost: substations, distribution networks, co-generation plants, critical loads, and wide-area monitoring.

And its setpoint logic can also act: capacitor banks, load shedding and transfer schemes. In figures: direct inputs up to 600 volts phase to phase, one or 5 amp C Ts, up to 4 gigabytes of memory, and operation from minus 20 to plus 70 degrees. Power network analysers, from Amperis.