Category: AC & DC Regenerative

The Ideal Regenerative Grid Simulator for Microgrid Testing

Microgrid Solar Wind Power Testing - NH Research (NHR)

NHR’s Regenerative Grid Simulator Accurately Emulates the Utility Grid

Regenerative Grid Simulator Model 9410 - NH Research (NHR)If you’re looking for a regenerative grid simulator or grid emulator, NHR’s 9410 has key competitive advantages over the market. NHR’s Regenerative Grid simulator is ideal for simulating complex power disturbances ideal for testing micro-grid and smartgrid applications.

NHR’s Regenerative Grid Simulator (9410) is a unique four-quadrant bi-directional AC/DC source that simulates the utility voltage and regenerates power sourced by grid-tied inverters. Greater than 90% of power is returned to the facility thereby providing significant energy savings. The 9410 is used as a grid simulator, or emulator for testing PV inverters and other grid-tied products for compliance to IEEE 1547, UL 1741, and global industry standards. A wide-range of AC conditions can be emulated including phase imbalance (in voltage and/or phase angle relationship), voltage sag, frequency changes and harmonic injection.

Modular and Scalable Power

The Regenerative Grid Simulator (9410) is flexible in both output form and power level. Output can be AC or DC and the AC can be single, split or 3-phase. Frequency is programmable between 30 and 100 Hz. Power is scalable from 4 kW to 96kW. With this broad selection of power, phase configuration and frequency, this grid simulator provides the flexibility to test the widest range of grid-tied products. The included measurement system also eliminates the need for additional power meters, DMMs, oscilloscopes, or spectrum analyzers.

3 Channel Multiple Configuration - NH Research (NHR)

Figure 1 – 3 channels with multiple configuration possibilities

Accurate Emulation of Complex Power Disturbances

The Regenerative Grid Simulator (9410) is able to replicate power line disturbances through a combination of user-definable waveforms and Macros. User-defined waveforms permit generation of non-sinusoidal voltages including asymmetrical inflections, transient anomalies, voltage harmonics, or any other irregularity which can be drawn as a single-cycle. The grid simulator can emulate sub-cycle transients, phase jumps and multi-cycle line conditions as required.

Simulating Voltage Harmonics - NH Research (NHR)

Simulating Area EPS Voltage Harmonics

Simulating Sub-cycle Transients - NH Research (NHR)

Simulating Sub-cycle Transients

Simulating Phase Jump - NH Research (NHR)

Simulating Phase Jump

Simulating Abnormal Voltages - NH Research (NHR)

Simulating abnormal voltages (sags, swells & drop outs)

This modular Grid-Simulator is used to verify product AC performance while a 9200/9300 Bi-directional DC Source may be used to emulate any energy storage system.

For more information, please visit our product webpage or contact us for a quote.

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Applications Include:

  • Grid Simulation: Microgrid, Smartgrid systems
  • V2G, ESS
  • On-board Chargers, Grid-aware Chargers
  • Grid Utility Test
  • PV/Grid Tied Inverter Test
  • Compliant with UL1741, IEEE1547 and similar grid-tied standards world-wide
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Regenerative AC Load with 4 Quadrant Functionality

EVs Charging - NH Research (NHR)

Bi-directional AC Load Accurately Emulates Complex Load Profiles

If you’re looking for a regenerative AC load with advanced capability, NHR’s 9430 has key advantages over the market. NHR’s Regenerative AC Load is ideal for simulating almost any complex linear or non-linear load.

The 9430 is a current-regulated, 4-quadrant AC load with selectable phase inputs/outputs and a built-in waveform digitizing measurement system. Greater than 90% of power is returned to the facility thereby providing significant energy savings. Applications include testing of Vehicle to Grid (V2G), solar and grid-tied inverters, UPSs, AC sources, rectifiers, circuit breakers and fuses.

AC Load 4-Quadrant Operation Offers Bi-directional Capability

Regenerative AC Load Model 9430 - NH Research (NHR)The most unique feature of NHR’s Regenerative AC Load (9430) is the ability to operate in all 4-quadrants. The 4-quadrant AC load allows for emulation of current draws historically requiring use of discrete components such as capacitors and inductors. Multiple bi-directional power conversion stages take place internally to generate the AC or DC current output depending on the hardware operating mode.

This bi-directional capability significantly expands load simulation relative to 2-quadrant AC loads. The Regenerative AC Load (9430) allows creating the reverse current caused by inductive or capacitive loads (low power factors). Power is sent back to the UUT (source) during part of the AC cycle (Fig. 1). In this manner, the 9430 accurately duplicates real-world reactive electrical power flows.

Inductive Load Bi-directional Waveform - NH Research (NHR)

Figure 1 – 0.5 PF Inductive Load waveform showing bi-directional power flows.

HIVAR design provides reactive loading without derating True Power

This advanced design feature allows for testing high reactive load input power without the customary reduction of true power (Watts) normally required with conventional loads. The HiVAR design provides testing sources with reactive power (VARs) as large as 2.6 x true power (Watts). All 9430 Loads are rated both for true power and apparent power. For instance, a 12kW AC load is also rated for 31.5kVA.

This Regenerative AC Load (9430) supports full-time current loading including at full Line-Neutral voltage up to true power rating of the system, providing a wider operating envelope. By comparison, traditional AC loads are resistive, and are unable to provide a true power factor shift, and are able to only draw current up to the thermal power rating of the system.

Constant Power Envelope - NH Research (NHR)

Constant Power Envelope for 9430-12 operating as 1-Φ-load

Regenerative AC Load with Several Emulation Modes

To provide testing under the broadest range of loading conditions, the Regenerative AC Load (9430) will operate in several emulation modes. Constant Current (CC) Mode provides current to be drawn constantly, making it suitable for linear, non-linear and regulation loading. Constant Resistance (CR) Mode allows the load to emulate a power resistor with a unity power factor. Constant Power (CP) Mode emulates a load such as a switching power supply. Constant Apparent Power (CS) Mode expressed as VA, is a vector quantity where there is both real power and reactive power. Constant RL (CRL) Mode emulates a resistive load with an inductive component such as a motor.

User-defined Waveforms

The Regenerative AC Load (9430) has an easy to use graphics editor to create waveforms based on current, power and crest factor. Easily duplicate waveform distortions or transient events such as spikes, dropouts or any other anomaly that can be drawn as a single cycle. A second powerful user-defined waveform tool is the Macros. These are pre-programmed sequence of settings where each new setting is effective for a sub-cycle, any number of cycles or for a fixed amount of time.

For more information, please visit our product webpage or contact us for a quote.

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Applications Include:

  • Full Line Disturbances at Any Power Factor
  • Grid Utility Test, Inverter Test, UPS Test
  • EV Load Testing
  • Switch, Fuse Test
  • Linear and Non-linear Loading, Inductive and Capacitive Loading Requirements
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The Benefits of Regenerative Loads & Sources

Utility Grid Testing - NH Research (NHR)

Intro to Regenerative Loads & Sources

Traditional loads, either air-cooled or water-cooled, convert the unit-under-test’s (UUT) output power into heat waste whereas regenerative loads recycle the UUT output power back onto the facility or UUT in the form of re-usable electricity. This allows the test system to lower the total electrical usage while significantly reducing waste heat. For example a regenerative load with > 90% efficiency would return more than 90% of the UUT’s output power back to the facility and convert less than 10% of the UUT power into heat.

Traditional Electronic Loads vs. Regenerative Loads

An electronic load converts 100% of the discharge power (P = V*I) directly into heat. Unlike resistors, electronic loads are able to provide more sophisticated loading profiles such as constant current, constant voltage, and constant power, in addition to constant resistance. The load profile can be changed dynamically without disconnecting the UUT. Air-cooled electronic loads dissipate the waste heat into the air and can be used anywhere in a laboratory or manufacturing space as long as there is sufficient space or air-chiller capacity. Water-cooled electronic loads dissipate the waste heat through a water connection, which limits where these loads can be used. Testing may also get halted when the water-chiller system is under maintenance.

Regenerative electronic loads convert discharge power (P = V*I) back into usable electricity for the facility, thereby increasing flexibility in two ways. First, the total power demand and associated electrical costs are reduced. Second, regeneration creates significantly less waste heat, which in turn reduces  the energy and equipment required for facility cooling. This allows maximum flexibility when planning, upgrading, or rearranging laboratory or manufacturing workspaces.

Regeneration Significantly Reduces the Cost of Heat

Using regenerative AC and DC loads and sources dramatically reduces the total amount of power required from the utility.  This is because the UUT can use the power from both the utility connection and the power returned by the regenerative load. This directly reduces the total amount of power used by the facility to conduct the required testing, the amount of waste heat, and the power to remove the heat. Additionally, the total cost of ownership of traditional loads often includes far more than just the initial purchase of the load. Traditional loads imply more electrical usage and higher electrical usage may require electrical system upgrades to support additional test stations. Each new station will generate significant amount of waste heat, which may require facility modifications such as new air-handlers or water-chiller connection points. All these costs can be associated with simply trying to remove waste heat.

NHR Regenerative Test Solutions

NH Research (NHR) provides regenerative AC and DC loads with expandable power to meet future higher test-power needs. This modular design allows for maximum flexibility in test by providing unmatched configuration options as well as future scalability. Both AC and DC products are bi-directional allowing them to reverse power flow using the same internal electronics.

Regenerative AC/DC Loads and Sources:

To learn more about potential cost savings , download our Regenerative Loads and Sources Application Note.

Download “Regenerative Loads & Sources” App Note