Electrical measurement cluster on zigbee?

Hi there,
Currently I am working on custom hardware embedded with siliconlabs mgm13p in which I have defined electrical measurement cluster id with 2-3 attributes for reading and sending data like voltage, current and power. After pairing node, on the template of electrical measurement cluster it displays value -0.1 W, means it is reacting on power attribute only. I edited in config file to get voltage value I am sending

  - platform: template
    sensors:
      net_voltage:
        friendly_name: "Voltage"
        value_template: "{{ state_attr('sensor.zha_fe0ae080_6_2820', 'rms_voltage') }}"
        unit_of_measurement: 'v'

But in created template it is showing ‘NONE’. By the document, If attribute is present it returns value and if not it shows none. I didn’t find any document on this. What should I do?