DG PV Controller
DG synchronization with solar (DG PV synchronization system).
When the grid power isn’t available, DG (diesel generator) can be used as reference power to an on-gird solar power plant. This type of PV DG synchronization can be possible with any make of grid-tie solar inverters. As long as connected load (kW) is lesser than power generated from on-grid solar power plant this DG PV synchronization is safe. But if gird-tie solar power plant generates any surplus power. This surplus power will reverse back to DG (generator) and damage it. DG PV controller is required solar dg synchronization.
DG PV controller
DG PV controller is the device used to protect DG (diesel generator) from the surplus power generated from the PV plant. DG PV controller is also known as Zero Export Device. DG PV controller enables solar system owners & operators to limit the amount of solar power that their systems export to the DG (diesel generator).
DG PV controller limits the amount of energy generated by on-grid solar inverters by adjusting the set point of the gird-tie inverters. Inbuilt power analyzer of DG PV controller measure the total power at the point, DG couples (electrically couple) with the load and compares this with the set point of DG PV controller.
When the load on DG (diesel generator) is above this set point, DG PV controller ramp up the solar power. And if the load on DG is below this set point, DG PV controller will ramp down the solar power.
Continuous running generator at load lesser than 30% of its rated capacity affects it negatively. DG PV controller makes sure that DG is 30% loaded.
Can the solar plant (PV Plant) synchronizes with Grid power and DG power
Solar power plant (PV plant) can be synchronized with both Gird power as well as DG power. Any make of gird-tie (on-gird) solar inverter can be used for the synchronization of PV plant with Gird and DG (generator). DG PV controller is required to save the DG from the surplus power (power generation > power required) of the solar power plant.
Solar Grid DG management system
DG PV controller (which is also called Zero Export Device) can also work as the solar grid dg management system. Most of the built-in monitoring systems supplied by the inverter manufacturers are stand-alone systems providing the performance data of the inverter or solar power plant. DG PV controller (also called Zero Export Device) has inbuilt RMA (data logger) which helps solar power plant owner to monitor the performance of the solar power plant in conjunction with the Grid as well as DG loading.
DG PV Controller Price
Price of DG PV controller varies from 8,000 Rs (IND) to 1,50,000 Rs (IND), as per the plant size and numbers of DG sets but remain same irrespective of gird-tie solar inverter make like ABB, SMA, Hitachi, Consul Neowatt, Huawei, Solar Edge, Kaco, DELTA, Solis, Kirloskar, polycab, Sungrow, Growatt, Fronius, REFU Sol, Schneider, Zever solar and many more.
Diesel generator and solar synchronization procedure
Step by step procedure of synchronization of DG (Diesel generator) with solar power plant (PV plant).
Step#1: Install a (set) of current transformer(s) at the coupling point of diesel generator and load. For the measurement of power drawn from DG.
Step#2: Connect the output of current transformer(s) to DG PV controller via 10 core, 1.5 Sqmm cable.
Step#3: Take one power source (voltage source) before coupling point of DG and load to DG PV controller via 3 core, 1.5 Sqmm cable. For the internal power requirements of DG PV controller and voltage reference for power analysis.
Step#4: Connect grid tie (on-gird) PV inverter (solar inverter) with DG PV controller via LAN (CAT 6) cable.
Step#5: Connect DG PV controller to local internet via LAN (CAT 6) cable. For the online monitoring of PV plant, DG and Grid.
Step#6: In DG PV controller, set the sharing point of load on DG SET at 30% of DG capacity, to keep DG SET minimum 30% loaded.
How does DG PV controller work?
For the synchronization of PV plant (solar plant) with DG (diesel generator), DG PV Controller is require, with the set the sharing point at 30%.
But why 30% ??, operating a DG set at load less than 30% of rated capacity for extended time periods impacts the unit negatively. These impacts includes engine exhaust slobber, which is also known as exhaust manifold slobber or wet stacking. Engine slobber is a black, oily liquid that can leak from exhaust manifold joints due to extended low- or no-load scenarios. Running at high idle with little or no load reduces the heat in the cylinder, allowing unburned fuel and oil deposits to leak through the exhaust slip joints. Click here to learn more about the same
Refer below for the ideal loading on DG SET
To understand the sharing of load between DG SET and PV plant during a power failure, let's take an example, where PV plant is producing 100kW, DG SET Rating is 250kVA (200kW) and the total load is 120kW then suddenly power failed
For the first few minutes whole load is shifted on DG SET, because Solar inverters take few minutes to restart or start producing power
During these few minutes, integrated power analyzer of ZED Advance (DG PV Controller) monitor the load, and communicate with the solar inverter, so that during starting Solar inverter produce power as per set point to keep DG set 30% loaded.
So 120kW of load will be shared between DG SET and PV plant, i.e 60kW on DG SET (30% of 200kW or 250kVA) and PV plant will produce 60kW instead of 100kW.
Now just like in Zero Export Case, either Load varies or PV plant's output power varies.
Power Generation of PV plants varies
In case of load varies, if the load goes below 30% of DG SET rating, ZED Advance (DG PV controller) will completely Shutoff the PV plant.
And when the power comes back, PV plant will start running normally.