公开(公告)号：US20220131681A1

公开(公告)日：2022-04-28

申请号：US17600154

申请日：2020-02-13

Applicant: Hitachi, Ltd.

Inventor： Tatsuya MARUYAMA ,  Mitsuyasu KIDO ,  Shoji YOSHIDA ,  Kazuhisa TAKAMI ,  Takamichi ENDO

IPC: H04L7/00 ,  H04L7/04

Abstract: In the related art, since there is a difference in communication delay time in a round-trip communication path due to packet clogging in a network configuration using a network relay device, there is a problem that time cannot be synchronized. In order to solve the above problem, in the present invention, a time synchronization unit 131 is controlled by the time synchronization control unit 130 to perform time synchronization once, delays of an egress path and an ingress path of the time packet on the basis of the synchronization time are calculated, and time synchronization processing is executed using a time of the time packet in a case where the calculated values are equal to each other.

公开(公告)号：US20210373065A1

公开(公告)日：2021-12-02

申请号：US17290284

申请日：2019-08-22

Applicant: HITACHI, LTD.

Inventor： Kazuhisa TAKAMI ,  Shoji YOSHIDA ,  Mitsuyasu KIDO ,  Tatsuya MARUYAMA

IPC: G01R31/12 ,  G01R31/14 ,  G01R31/52

Abstract: A partial discharge detection apparatus includes low-speed and high-speed AD converters. The low-speed AD converter converts an analog signal of an AC waveform flowing through a power cable into a digital signal. The high-speed AD converter converts an analog signal of a partial discharge current into a digital signal. The analog signal is in a plurality of Nyquist frequency domains defined for each of two different types of sampling frequencies. The partial discharge is detected by a partial-discharge-detection digital signal processing unit based on the maximum value or the sum of a current value obtained from the digital signal of the partial discharge current obtained by the conversion of the high-speed AD converter, for each phase of the AC waveform, which is obtained from the digital signal of the AC waveform flowing in the power cable. The digital signal is obtained by the conversion of the low-speed AD converter.

公开(公告)号：US20140098706A1

公开(公告)日：2014-04-10

申请号：US14044895

申请日：2013-10-03

Applicant: Hitachi, Ltd.

Inventor： Tatsuya MARUYAMA ,  Tsutomu YAMADA ,  Mitsuyasu KIDO ,  Shoji YOSHIDA

IPC: H04J3/06

CPC classification number: H04J3/0638 ,  H04J3/0667 ,  H04L47/30

Abstract: Communication control equipment is connected to a plurality of communication control equipment via a network and is configured to be time-synchronized with the plurality of communication control equipment by using a time synchronization procedure using a communication including at least request packets and acknowledgement packets. The communication control equipment includes a receiving-interval measurement section configured to measure a receiving interval of request packets from the plurality of communication control equipment; and a queuing-occurrence determination section configured to detect conflict of the request packets from any of the plurality of communication control equipment on a basis of the receiving interval of the request packets measured by the receiving-interval measurement section. The communication control equipment is configured to determine whether to transmit an acknowledgement packet to the communication control equipment that has transmitted the request packets based on a detection result of the queuing-occurrence determination section.

Abstract translation: 通信控制设备经由网络连接到多个通信控制设备，并且被配置为通过使用至少包括请求分组和确认分组的通信的时间同步过程与多个通信控制设备进行时间同步。 通信控制设备包括接收间隔测量部分，被配置为测量来自多个通信控制设备的请求分组的接收间隔; 以及排队发生判定部，其基于由所述接收间隔测量部测量出的所述请求分组的接收间隔来检测来自所述多个通信控制设备中的任一个的所述请求分组的冲突。 通信控制设备被配置为基于排队发生确定部分的检测结果来确定是否向已发送请求分组的通信控制设备发送确认分组。