Kabushiki Kaisha Toshiba

Akira Kawarada

Masashi Ito

Hideaki Sugiura

Takahiro Mori

Tomonori Nishida

Kazuto Fukushima

Michihiko Inukai

Akinori Hirose

According to an embodiment, a time synchronization client includes one or more processors. The one or more processors are configured to perform time synchronization according to time information received by communicating with a time synchronization server at every synchronization period, and determine a second synchronization period shorter than a first synchronization period of when synchronization accuracy is a target level or more, as the synchronization period, when an elapsed time from activation of the time synchronization client does not exceed a judgment time.

Time synchronization client, synchronization method, computer program product, and synchronization system

According to an embodiment, a management device includes a calculator and a notifier. The calculator calculates a time offset for each of a plurality of master devices each performing, when a measured time reaches a certain time, time synchronization with a slave device, which is a management target, at the measured time. The notifier notifies each master device of a change notification causing the master device to change the measured time in the master device to a time obtained by offsetting the measured time with the time offset.

Management device, system, and method

A protective relay system includes plural protective relay devices protecting a power system based on electrical quantity data from the power system, and a communication between the protective power devices is performed via a network. The protective relay device includes a clock unit periodically clocking a timing at which sampling is performed on an electrical quantity of the power system, a relay computing unit performing a relay computation based on the electrical quantity data having undergone the sampling and electrical quantity data received via the network, a random-number creating unit creating a random number, and a synchronization-frame processing unit setting a timing of sending a synchronization frame to another protective relay device via the network based on the random number created by the random-number creating unit.

Protective relay system and protective relay device

According to an embodiment, an estimation apparatus includes first to fourth obtainers and an estimator. The first obtainer obtains, for each slave node, a piece of synchronization information in a network configuration including: nodes including a master node serving as a time synchronization source, one or more slave nodes serving as time synchronization destinations, and relay nodes; and paths connecting the nodes. The second obtainer obtains, for each path, a piece of band information. The third obtainer obtains, for each path, a piece of traffic information. The fourth obtainer obtains, for each relay node, a piece of path information. The estimator estimates a predetermined relay node causing reduction of accuracy of time synchronization between the master node and the one or more slave nodes, based on the one or more pieces of synchronization information, the pieces of band information, the pieces of traffic information, and the pieces of path information.

Estimation apparatus, system, and computer program product

According to an embodiment, the transmission processor of the master terminal includes a sending/receiving processor which sends a synchronization request demanding packet to a particular slave terminal and sends a synchronization reply packet when receiving a synchronization request packet from the slave terminal that has received the synchronization request demanding packet, and a synchronization controller which calculates a synchronization band from the time of the receipt of the data packet and from time information added to the received data packet to determine a synchronization state and which adjusts a correction amount in accordance with the synchronization state and sends an internal timing correction command to the timing generator.

Growing community of inventors

Fuchu, Japan

Akira Kawarada