Market demand for Distributed Resource (DR) products such as PV inverters and wind energy systems is steadily growing as the world strives for clean renewable energy sources. This demand has created a need for rigorous regulation testing to standards like UL 1741SA / IEEE 1547 / IEC 62116 which ensure proper and safe operation of on-grid products. It has become critical to manufacturers to conduct these tests in order to prove compliance and to relieve product liability concerns. Chroma's new 61800 family of Grid Simulators has been designed to fulfill these test requirements by providing a full 4 quadrant, fully regenerative, grid simulator with advanced features for compliance, safety and product verification testing.
The 61800 Regenerative Grid Simulator is a full 4 quadrant, full regenerative, AC power supply designed for common electrical product testing such as home appliances, and industrial electronics needing a programmable input source. In additional, the 61800 is designed to simulate grid characteristics for testing PV inverter and on-line UPSs. As shown below, power can be both sink and source from the UUT seamlessly to support different types of applications. In cases where the UUT sources current a detection circuit will sense the excess power and recycled it back to the grid.
In addition to supplying clean, precise and stable AC voltage for regular applications, the 61800 is capable of simulating various types of distorted voltage waveforms and transient conditions required by product validation testing. These are accomplished as shown below using built-in programmable waveform functions like the LIST/STEP/PULSE modes. The STEP and PUSLE functions allow users to perform single or continuous step changes of output voltage while the LIST mode is a more versatile function as it allows users to compose complex waveforms of up to 100 sequences. Voltage waveforms required by immunity specifications such as IEC 61000-4-11 (short interruption and voltage dropout) can be easily achieved by the 61800 Regenerative Grid Simulator.
The SYNTHESIS function allows users to create periodic harmonic voltage waveforms of up to 50 orders based on a 50/60Hz fundamental frequency. The INTERHARMONIC function allows users to perform frequency sweeps ranging from 0.01Hz to 2400Hz on top of the 50/60Hz fundamental frequency. This special function assists users in locating resonance points.
The 61800 Regenerative Grid Simulator is capable of simulating various test conditions such as voltage distortion, frequency variation and more in order to meet Micro Grid test requirements. Most importantly, the regenerative feature of the 61800 series can feed the power generated by the Discrete Generator (DG) on the micro grid and back to the AC grid with high efficiency. The input side of 61800 series product has been specifically designed to be isolated from the main grid. Hence additional isolation for a Discrete Generator (DG) on a Micro Grid is not required.
The 61800 series Regenerative Grid Simulator is capable of meeting the following regulations designated for Grid Tied Discrete Generator testing for IEEE 1547 / IEC 61000-3-15 / IEC 62116:
- Voltage Abnormality Test
- Frequency Abnormality Test
- Anti-islanding Test
- Low Voltage Ride Through Test
- Immunity Test (IEC 61000-4-11/-4-34)
- Limit Test (IEC 61000-3-2/-3-3)
The 61800 Regenerative Grid Simulator provides an effective energy saving solution as the energy generated by a Discrete Generator (DG) is fed back to the grid with high efficiency instead of being dissipated as heat during operation.
The Low Voltage Ride Through (LVRT) function of grid tied PV inverter clearly defines that when an abnormality occurs on the main AC grid (such as a voltage drop), the PV inverter must remain operable and sustain the main AC grid for a certain specific time period. For instance : the BDEW standard requires the PV inverter to remain operable and delivering reactive power for at least 150ms when the grid voltage has dropped to 15% of the nominal value.
The 61800 Regenerative Grid Simulator is fully capable of meeting the LVRT test requirements, as the user can program the required transient test conditions through implementation of the LIST mode function, which provides a minimum time resolution setting of 0.1ms. Moreover, the user can also study and evaluate the impact on PV inverter performance due to grid line voltage distortion, by implementing the harmonic synthesis function of the 61800 series product. The frequency resolution of the 61800 is 0.01Hz which meets the BDEW requirement.
By incorporating the 61800 Regenerative Grid Simulator with the 8000 ATS and RLC load, the test system is capable of meeting IEEE 1547/IEC 62116 test requirements for Anti-islanding.
The external voltage programming input of the 61800 series Regenerative Grid Simulator allows users to feed any AC+DC waveform from an arbitrary signal generator and to amplify the signal accordingly. It can be used to simulate the real mains supply waveforms observed in the field or implemented with real-time digital simulator for HIL (Hardware In Loop) applications. The delay time from external voltage programming input to actual voltage output is approximately 100μs.
The 61800 series support Master-Slave parallel operation, which allows users for further extend the output power capability by connecting multiple units in parallel for higher power test application. Please refer to the following table as the combination allowed for parallel connection of different 61800 models.
Note*1: The maximum number of parallel unit for 61830/61845/61860 is 5 units.
Note*2: The maximum number of parallel unit for 61800-100 model is 8 units.
Note*3: The maximum number of parallel unit for 61800-100 (800VLN) is 3 units.
The 61800-100 (800VLN) model with integration of external 800VLN step up transformer is capable of meeting the high voltage grid connected PV inverter, PCS products with AC voltage up to 1000VLL related test requirements, such as: grid connected performance, voltage/frequency adaptability, high voltage ride through, etc. The 61800-100 (800VLN) also support parallel output function to meet the needs of high voltage and high power test requirements.
▲ Parallel connection of 3 sets of 61800-100 (800VLN) for 315kVA output power rating
The 61800 series further extends its test application capabilities by including optional functions such as B618000: Regenerative AC load function and B618002: 120kVA 800VLN XHV function.
The regenerative AC load function consists of various modes such as CC Rectified mode, CP Rectified mode, CR mode, CC Phase lead/lag mode and CP Phase lead/lag mode.
The Rectified Mode is capable of simulating non-linear rectified loads with characteristics similar to Chroma 63800 series AC load where the voltage andcurrent operate at the 1st and 3rd quadrant. The Rectified Mode supports both CC and CP functions with current, power and CF as parameter settings.
The phase lead/lag mode with phase angle setting ranging from 90 degree ~ -90 degree will simulate the corresponding voltage and current condition under an inductive or capacitive type load. Please note the current waveform is sinusoidal under the Phase Lead/Lad mode (current, PF and phase angle as parameter settings) and when the phase angle setting is in the range of 90.1 degree ~ 180 degree (-90 degree ~ -180 degree), the 61800 will become a current source. The regenerative AC load function is mainly intended for EVSE charging station, hybrid PV inverter, PCS, UPS, and micro-grid related test applications.
Please refer to the following as 61800 models support list for AC load function:
The B618002 800VLN XHV option is for achieving high output phase voltage up to 800VLN (1385VLL) by connecting two 61860 in series with high performance output voltage transient capability which is unmatched by the implementation of step up transformer. The B618002 XHV option is mainly intended to meet the test requirement of HV PV inverter with line voltage up to 1000VLL.
Please refer to the following table as the combinations allowed for high voltage series connection of different 61800 models:
Note*1: B618002: 800VLN XHV function
Note*2: B618005: 900VLN XHV function.