A power management system comprising: an operation terminal configured to perform a remote operation of an equipment (110; 120; 130; 150); and a control device configured to receive an access request from the operation terminal, transmit a request command to the equipment (110; 120; 130; 150), in response to reception of the access request, and receive a response command for the request command, from the equipment (110; 120; 130; 150), wherein the operation terminal comprises a user interface configured to notify a user of information specifying an expiration timing of a response waiting timer that defines a transmission interval or a reception interval of the request command, and the response waiting timer is managed by the control device, and configured to expire in response to reception of the response command, or expire with lapse of time corresponding to a timer value of the response waiting timer, the control device is configured to activate the response waiting timer in response to transmitting the request command to the equipment (110; 120; 130; 150), avoid transmitting a next request command to the equipment (110; 120; 130; 150) during the response waiting timer is running, and the operation terminal is configured to receive from the control device, a timer expiration notification indicating the expiration of the response waiting timer, and notify the information specifying the expiration timing in response to receiving the timer expiration notification from the control device, wherein the operation terminal is configured to notify information indicating that the next access request cannot be received in response to the transmission of the access request, and notify information indicating that the next access request can be received in response to the reception of the timer expiration notification. an operation terminal configured to perform a remote operation of an equipment (110; 120; 130; 150); and a control device configured to receive an access request from the operation terminal, transmit a request command to the equipment (110; 120; 130; 150), in response to reception of the access request, and receive a response command for the request command, from the equipment (110; 120; 130; 150), wherein the operation terminal comprises a user interface configured to notify a user of information specifying an expiration timing of a response waiting timer that defines a transmission interval or a reception interval of the request command, and the response waiting timer is managed by the control device, and configured to expire in response to reception of the response command, or expire with lapse of time corresponding to a timer value of the response waiting timer, expire in response to reception of the response command, or expire with lapse of time corresponding to a timer value of the response waiting timer, the control device is configured to activate the response waiting timer in response to transmitting the request command to the equipment (110; 120; 130; 150), avoid transmitting a next request command to the equipment (110; 120; 130; 150) during the response waiting timer is running, and the operation terminal is configured to receive from the control device, a timer expiration notification indicating the expiration of the response waiting timer, and notify the information specifying the expiration timing in response to receiving the timer expiration notification from the control device, wherein the operation terminal is configured to notify information indicating that the next access request cannot be received in response to the transmission of the access request, and notify information indicating that the next access request can be received in response to the reception of the timer expiration notification.