2. Power Sensors

Power Sensors

The power sensors are the "first step". They register the power in [W] (watt) at any given moment. Below is an overview and a short description of the custom power sensors included in "Huawei Solar PEES package" created on basis of the three types of sensors sensor.inverter_input_power, sensor.power_meter_active_power and sensor.battery_charge_discharge_power from the "Huawei Solar integration by wlcrs".

Name	Description
Power Inverter #1 Input (ts) sensor.power_inverter_1_input_ts	Power feed into the inverter or the effeciency corrected power feed from inverter #1. See note below.
Power Inverter #2 Input (ts) sensor.power_inverter_2_input_ts	Power feed into the inverter or the effeciency corrected power feed from inverter #2. See note below.
Power Inverter Input Total (ts) sensor.power_inverter_input_total_ts	Sum of power feed into inverters in case you have multiple inverters (do not use this sensor for energy calculations).
Power Export (ts) sensor.power_export_ts	Sum of power exported to grid. This includes power generated from the solar PV and power discharged to grid from the battery.
Power Export Yield (ts) sensor.power_export_yield_ts	Power exported directly to grid from the solar PV yield.
Power Import (ts) sensor.power_import_ts	Sum of power imported from grid. This includes power consumed in the house and power imported to charge the battery.
Power Battery Charge (ts) sensor.power_battery_charge_ts	Sum of power generated by the solar PV and power imported from grid used too charge the battery.
Power Battery Discharge (ts) sensor.power_battery_discharge_ts	Sum of power discharged from the battery either too be consumed in the house or exported too the grid.
Power House Load (ts) sensor.power_house_load_ts	Sum of power consumed in the house, including power from solar PV, grid and battery. This corresponds to the power which you would have had to import / purchase without the solar PV.
Power Battery Charge Grid (ts) sensor.power_battery_charge_grid_ts	Power imported from grid to charge the battery.
Power Battery Charge Yield (ts) sensor.power_battery_charge_yield_ts	Power generated by the solar PV used to charge the battery.
Power Battery Discharge Grid (ts) sensor.power_battery_discharge_grid_ts	Power discharged from the battery and exported to grid.
Power Battery Discharge House (ts) sensor.power_battery_discharge_house_ts	Power discharged from the battery and consumed in the house.
Power House Load Grid (ts) sensor.power_house_load_grid_ts	Power imported from grid and consumed in the house.
Power House Load Yield (ts) sensor.power_house_load_yield_ts	Power generated by the the solar PV and consumed in the house.

💡 Note: By default the sensor.power_inverter_1_input and sensor.power_inverter_2_input will display the power feed into the inverter, corresponding 1:1 to the input power without taking the inverter efficiency into account. This may cause the yield and therefore also the house load to be slightly too high (approximately 2 - 3%).

Efficiency Corrected Power Input Sensor

The "Huawei Solar PEES package" includes the option correct the power input sensor for inverter efficiency. Here is a short description of how to set up and adjust your efficiency corrected power input sensor.

• Toggle the on/off switch to "on" to activate the "efficiency corrected power input sensor". Be sure to chose the toggle switch for the type of inverter that you have (single or three phase).
  

• In the card that appear below, chose the model of your inverter in the drop down menu.
  

• The slider for the "Operating voltage" is used to adjust the efficiency of the inverter. The rated voltage of your inverter, represents the voltage at which your inverter has the highest efficiency. For the Huawei SUN2000 3/4/5/6/8/10KTL-M1 (three phase) inverters, the rated voltage is 600 V. For the Huawei SUN2000 2/3/3.68/4/4.6/5/6KTL-L1 (single phase) inverters the rated voltage is 360 V.
  You can use the slider to adjust the operating voltage within the operating range of your inverter. Any adjustmens made that deviates from the rated voltage will decrease the efficincy, but with slightly different profiles. The profiles used match the efficiency curves in the datasheet from Huawei. There is a linear interpoleration between the known values.
  You can use the "History" information in the FusionSolar app to set your approximate voltage. With more than one string you will have to estimate an average. The "goal" is not to set it "correct" voltage, because there is not one "correct" value. The "goal" is to set the operating voltage to a value, which will give you the most accurate energy output.
  

• The slider for the "Overall factor" is a bit more straight forward. This slider will, as the name suggests, increase or decrase the overall efficiency of the efficiency corrected power input sensor. This is very powerfull and therefor the range of the slider is limited and the increments are small. Set to 100% the slider has no effect.

To simplify the differense between the two slides without getting to technical, think of the overall factor as a "parrallel adjustment" (up and down) of the efficiency curve, whereas the operating voltage is "adjusting the "profile of the curve" with some reduction of efficiency".

In depth on the Efficiency Corrected Power Input Sensor

❗ Work In Progress ❗

Here is an overview and a short description of the parameters used in the "Efficiency Corrected Power Input Sensor". Note that you need to confirm / edit the first 3 parameters to fit your solar PV installation.

Name	Description
inverter_rating <your input>	The inverter rating is what is referred to as the "rated output power" of your inverter according to the Huawei data sheet (which is the same unique number used in the name of your inverter just in W and not kW).
overall_factor <your input>	The overall factor is used to make global adjustments to the calculated power output. As default this value is set to 1.000 (one). Be aware that even minor changes to this value will have e huge impact overall.
operating_voltage <your input>	The operating voltage is a manually corrected efficiency reduction factor. As the efficiency graphs show, each inverter models has an optimal voltage (rated voltage) and when actual voltage from the PV system deviates from the rated voltage the efficiency decrease. This parameter is used to adjust this decrease. The aim here is to make micro adjustments in order to get the correct yield and not to type in the "correct" voltage.
input_power	The input power is the power generated by the solar PV entering the inverter before the efficiency correction. This is the value from the sensor.inverter_input_power provided by the "Huawei Solar integration by wlcrs".
load_factor	The load factor relates to the x-axis on the efficiency graph in the data sheet from Huawei. It is the quotient of the input and inverter rating in percent.
efficiency	The efficiency is the load dependent efficiency of the inverter running with the rated voltage in percent - it is the efficiency before any correction for the operating voltage. The efficiency relates to y-axis on the efficiency graph in the data sheet from Huawei.
voltage_factor	The voltage factor is a correction/reduction factor in percent of the efficiency based on the manually set operating voltage. If the operating voltage is set equal to the rated voltage of the inverter, the voltage factor will be 0 (zero). If the operating voltage is set to one of the voltages shown in the data sheet from Huawei, the voltage factor will return a corresponding reduction.

Why use an efficiency corrected power sensor?

I presume you have a Huawei solar PV installation and if you have payed attention to your yield in the Fusion Solar app, at times you might also have noticed an unexpected behaviour of the sum of your yield.

Well first, we have Yield in the Statistics page, and we have Yield today in the Devices > Inverter > Real-time-info page and those two values do not add up.

• Yield does not include energy consumes from the battery, it is in some way corrected for system efficiency/loss. This is very apparent when you have a battery - but most will be able to spot a small decline of the value in the evenings after sunset. In days with some but very low yield the sum of "Yield" might even end up at 0 at the end of the day.

• Yield today has a different behaviour. I have not gone into depth of the deviations between the two, but it is very clear that "Yield today" is including discharging (not charging) of the battery. I have also documentation showing the value is being corrected during "yield-hours" - it simply completely halts the yield or decreases it significantly. This is not single time glitches I can assure you.

Hence there is no input in kWh (energy) from Huawei that meters the yield of your solar PV system without some correction, it makes sense to calculate the yield based on the power input measurement from the inverter which is provided by Huawei and the "Huawei Solar integration by wlcrs". The power sensor however is a measurement of the power input, not output from the inverter. Converting the DC solar power to AC or even conversion to DC to charge the battery, comes at a cost - the inverter efficiency.

There is additional information in the "Huawei Solar integration" - Wiki page - "Daily Solar Yield"

What is the default custom sensor in the "Huawei Solar PEES package"?

The default sensor.inverter_input_power from the "Huawei Solar integration" and sensor.power_inverter_1_input in the "Huawei Solar PEES package" does not take the inverter efficiency into account. This results in a too high yield (rated to approximately 2-3%) and therefore a to high consumption for the sensor sensor.house_load_yield. So why is this sensor used as default? Because it is simple, it works out of the box and is meant for those who are not comfortable editing yaml.

Why another efficiency corrected power sensor?

The "Huawei Solar integration by wlcrs" does provide the sensor.input_power_with_efficiency_loss which takes the inverter efficiency into account. I have not tested this sensor, but my assessment was and is, that it may cause inaccuracies and/or errors in the custom sensors included in the "Huawei Solar PEES package" due to the step-by-step adjustment of the efficiency.

What more do I need to know?

The "Efficiency Corrected Input Sensor" use three user specific inputs. Two of them are rather powerful tools to adjust the efficiency corrected output power from your inverter.

• inverter_rating This is simply the rated output power of your inverter.
• operating_voltage This is a user specific adjustment based on your own observations. Hence, we only have voltage metering pr. string and only power reading pr. mppt it is most likely not possible to use the voltage metering. The point here is also to use this parameter as an adjustment of the output - it is not to type in the "actual" voltage. Those of you with one string could arguably experiment with using the voltage metering. I'm not sure how the result may turn out.
• overall_factor The overall factor is as the name indicates a factor which adjust the overall power output in a linear fashion. I suppose this factor also could be used very creatively i.e. seasonal correction?

What does the efficiency corrected sensor take into account?

The "Efficiency Corrected Power Input Sensor" is based on the efficiency graph in the "Huawei Data Sheet". The graph is representing the efficiency of the inverter (% efficiency on the y-axis) at a given load (energy yield in % of the rated output on the x-axis).

Efficiency graphs from the Huawei Data Sheet. Single phase inverters (L1) to the left and triple phase inverters (M1) to the right.

The formula to calculate the inverter efficiency. {{ (( overall_factor * input_power * (efficiency + voltage_factor) / 100) | float(0) ) | int }}

Operating voltage The orange curve represents the inverter efficiency at the rated voltage (360 and 600V respectively). This is the optimal voltage for the inverter. The blue and the grey curve represents the inverter efficiency at voltages closer to the endpoints of the inverter operating voltages. As you can see the efficiency decline if/when the voltage deviate from the rated voltage of the inverter.

Setting the operating_voltage = rated voltage (360 and 600V respectively) will result in a efficiency output according to the orange curve.

Note: The goal here is to adjust the operating_voltage so that your inverter yield is as close as possible to the actual yield - not to try and approximate the actual voltage received by the inverter. Arguably they should be close though, but since we only have the voltage pr. string and the voltage pr. mppt tracker there is no right or wrong here.

The blue and the grey curve have been created a bit differently than shown on the efficiency graphs from Huawei. Deviation from the orange curve / the rated voltage is calculated as a reduction of the efficiency at rated voltage. Reduction herby is a delta value between the orange and the blue/grey line. If operating_voltage is set to the rated voltage, the reduction is 0 (zero). At any other voltages there is a reduction corresponding to the difference between between the orange curve for the rated voltage and the reduction curve reduction. There is used a linear interpolation of the reduction. Basically this means if you set the operating_voltage to any of the "outer point" voltages shown on the efficiency graphs from Huawei (260 or 480V on the L1 and 470 or 850V on the M1), the linear interpolation will return 1 (one) and the voltage_factor will return a delta value corresponding to the delta value between the orange curve and the blue/grey curve at any given load. This also means you are not limited to use a voltage between the "outer points".