Itech IT7900EP series regenerative grid emulator and regenerative AC load

The Itech IT7900EP series of regenerative grid emulators / regenerative AC load is an extension in Itech’s IT7900P series of AC/DC power supplies. The IT7900EP goes one step further in power (21kVA in 3U) as the standard IT7900P series. And in a master/slave configuration, we can therefore go up to 231kVA power in a 37U high 19’ rack. When racks are connected in parallel, we get to more like 1MVA of power.

Specifications IT7900EP series regenerative grid emulators

Let’s start with some basic specifications. The unit can be used as single-phase and three-phase regenerative AC power supply. The voltage of each phase is adjustable up to 350V L-N and the frequency range is from 16Hz – 150Hz + DC. The phases are also individually adjustable from 0° – 360°, allowing, among other things, an unbalanced grid to be simulated. In AC grid emulator mode, all kinds of grid contamination and harmonics can also be generated, even arbitrary waveforms.

The multifunctional IT7900EP AC power supply gives the user a choice of no less than four different output modes, namely AC, DC, AC + DC and DC + AC. There is thus the possibility of simulating both an AC grid and a DC grid. But also an AC grid where a DC offset applies. Even simulating a DC grid with an AC ripple is among the possibilities. Using the analogue interface option, Power Hardware In the Loop (PHIL) applications are also possible.

The grid emulator can both supply and absorb power with this power being fed back to the grid. An accurate Power Analyzer is also built-in with a multitude of measurements including harmonic distortion. With the built-in data logger function, you can also store measurement results in the internal memory for long periods of time.

Itech IT7900EP as AC/DC Load

This is where the P version simulator differs from the regular IT7900(E). On board is a four-quadrant regenerative AC/DC electronic load with impressive functionality. All conceivable operating modes are present and different RLC circuits can be easily simulated on demand. An anti-island test mode is also integrated in this unit. With this IT7900EP load functions, the user thus gets all the freedom and possibilities to simulate the behaviour of existing loads and also perform specific tests.

Functionality and standardisation tests

To save user time, the power supply is equipped with pre-programmed routine tests for IEC61000-4-11, 13, 14, 17 and 28 standards. Pre-compliance tests such as LVRT, a phase jump and frequency variations are also among the options. All possible grid distortions and events can be applied to the waveforms. Think of spikes, dips, interrupts, sags and surges. Using the STEP, LIST and PULSE modes, the various simulations can also be coupled. Harmonic distortions (up to the 50th at 50Hz or 60Hz) and interharmonic distortions can also be generated. The output impedance is also adjustable.

Measurement capabilities

The IT7900E also features an accurate and comprehensive Power analyser. Parameters such as Crest factor, power factor, active, reactive and apparent power are measured and optionally also stored in the internal memory for trend investigation. With the trend analysis function, these measured values can then be displayed graphically in detail.

Operation IT7900E high power programmable AC/DC power supply
Setting the correct test values is extremely easy using the 5-inch touchscreen display with menu structure, keypad, arrow keys and rotary knob. If you want to control the unit remotely, you can do so via the standard USB, LAN or CAN interface. There is also an optional GPIB interface and RS232+ analogue interface. Via the LAN interface and internal web browser, settings can also be easily made via PC.