A data transmission method, comprising: receiving, at a gateway , sensor measurement data collected by at least one monitoring device in an electrical substation; storing the received sensor measurement data in a data storage that is accessible to the gateway in a predetermined format; detecting a status of a connection between the gateway and a first network, the first network enabling communication between the gateway and a server ; and in response to detecting a disconnection between the gateway and the first network, sending the sensor measurement data to a user device via a second network hosted by the gateway to enable the user device to forward the sensor measurement data to the server ; wherein the first network is a wide area access (WAN) network, and the second network is a WI-FI network hosted by the gateway ; the method further comprising: receiving, at the user device , the sensor measurement data from the gateway via the second network hosted by the gateway ; detecting, a status of a connection between the user device and the first network, the first network enabling communication between the user device and the server ; and in response to detecting that the user device is connected to the first network, sending, via the first network, a first request for an access to the server ; and in response to receiving, via the first network, a first authorization to the first request from the server , sending the sensor measurement data to the server via the first network; and wherein receiving the sensor measurement data comprises: sending, via the second network, a request for the sensor measurement data to the gateway ; and in response to receiving, via the second network, a second authorization to the second request from the gateway , receiving the sensor measurement data at the user device ; and wherein receiving the sensor measurement data at the user device comprises: in response to receiving the second authorization that is based on a category and a geographical information associated with a user of the user device , receiving the sensor measurement data at the user device . receiving, at a gateway , sensor measurement data collected by at least one monitoring device in an electrical substation; storing the received sensor measurement data in a data storage that is accessible to the gateway in a predetermined format; detecting a status of a connection between the gateway and a first network, the first network enabling communication between the gateway and a server ; and in response to detecting a disconnection between the gateway and the first network, sending the sensor measurement data to a user device via a second network hosted by the gateway to enable the user device to forward the sensor measurement data to the server ; wherein the first network is a wide area access (WAN) network, and the second network is a WI-FI network hosted by the gateway ; receiving, at the user device , the sensor measurement data from the gateway via the second network hosted by the gateway ; detecting, a status of a connection between the user device and the first network, the first network enabling communication between the user device and the server ; and in response to detecting that the user device is connected to the first network, sending, via the first network, a first request for an access to the server ; and in response to receiving, via the first network, a first authorization to the first request from the server , sending the sensor measurement data to the server via the first network; sending, via the second network, a request for the sensor measurement data to the gateway ; and in response to receiving, via the second network, a second authorization to the second request from the gateway , receiving the sensor measurement data at the user device ; <EOS>