What Are Pacific Power Source Grid Simulators and Regenerative Loads Used For?

Pacific Power Source's grid simulators (RGS and GSZ series) and regenerative loads (RLS and ELZ series) are used to test equipment that connects to the electrical grid — solar inverters, EV chargers, data center power systems, and similar products. The grid simulators recreate the AC (and in some cases DC) conditions of a utility grid so a device under test can be evaluated against compliance standards, while the regenerative loads absorb and recycle power back to the grid instead of burning it off as heat. Both product families scale from roughly 1 MVA up to about 1.3 MVA, which puts them in the range of full-power, utility-scale test benches rather than bench-top lab equipment.

Grid simulators: RGS and GSZ series

A grid simulator is a programmable AC source designed to behave like the grid itself — including the disturbances a real grid produces. That means it can generate not just a clean sine wave but also voltage sags, swells, frequency shifts, harmonics, and other anomalies that compliance standards require a product to survive.

Pacific Power Source lists two regenerative grid simulator lines:

Both are described as regenerative, meaning power drawn by the device under test can be returned to the facility rather than dissipated. This matters at these power levels: a 1 MVA test running for hours converts a large amount of energy into heat if it is burned off conventionally, which drives up cooling requirements and electricity cost.

What grid simulators are used for

• Grid compliance testing — verifying that an inverter, charger, or power supply meets the ride-through, power quality, and interconnection requirements of a given grid code.
• PV inverter testing — the site highlights a dedicated SmartTS-PV Inverter Grid Compliance Test System, which pairs with this class of hardware for solar inverter certification work.
• EV and EV charging — testing onboard chargers and charging equipment against the AC conditions they will see in the field.
• Aerospace, military, and data center power — the same programmable-source capability applies wherever equipment must be validated against a controlled AC input.

Regenerative loads: RLS and ELZ series

A regenerative electronic load does the opposite job of a source: it absorbs power from a device being tested. The "regenerative" part means that absorbed energy is converted and returned to the grid instead of being turned into waste heat.

These are used when you need to discharge or load a product at high power — for example, testing an inverter's output, a bidirectional charger, or a power conversion system — and want to do it without a resistive load bank that would otherwise require substantial cooling and consume the full test power as waste.

Why "regenerative" is the key design choice

The practical difference between a regenerative and a non-regenerative test setup comes down to three things:

1. Energy cost — recycled power is not simply lost as heat, so long-duration high-power tests cost less to run.
2. Cooling and facility load — dissipating hundreds of kilowatts to over a megawatt as heat requires significant HVAC and electrical infrastructure; regeneration reduces that burden.
3. Test duration feasibility — tests that must run for extended periods become practical when the energy is recovered rather than burned.

The trade-off is that regenerative equipment depends on a suitable facility connection to accept the returned power, so it is not a drop-in replacement for a simple resistive load in every lab.

Choosing between the series

The two grid simulator lines and two load lines overlap in function, so the decision usually comes down to required power level and the specific test standard being targeted:

• If your test plan needs the highest listed capacity, the RGS and RLS series go to 1.296 MVA.
• If your requirement sits somewhat lower, the GSZ and ELZ series are listed at 1.1 MVA+.
• If your work is specifically PV inverter certification, the SmartTS-PV system is the purpose-built option rather than a general-purpose source.

For anything beyond these headline figures — accuracy, transient response, specific grid codes supported, or how a series integrates with the SmartSource Suite test software — the specifications on pacificpower.com are the authoritative source, since those details determine whether a given unit actually satisfies a particular compliance standard.