Abstract: A power distribution monitoring and control device of an embodiment includes an acquirer and a representative sensor selector. The acquirer acquires a voltage measurement value measured by a plurality of sensors having a communication function installed in a power distribution system. The representative sensor selector selects one or more representative sensors in which the voltage measurement value has a high degree of similarity with that of other sensors installed in the power distribution area from one or more sensors installed in a power distribution area in the power distribution system by referring to the voltage measurement value acquired by the acquirer.

Abstract: A power system stabilizing device includes an arithmetic unit that constructs a system model by collecting various kinds of system information, calculates a transient stability under an assumed accident condition beforehand, and selects, for each assumed accident in advance, a target solar power generator for shutdown and a target power generator to be disconnected to stabilize a power system, and a control unit that shutdowns the shutdown target solar power generator and disconnects the disconnection target power generator from the power system which are selected by the arithmetic unit when a system accident occurs.

Abstract: According to one embodiment, a system includes a battery to charge power and discharge a direct-current power to a converter, the converter supplying the converted power to a power system, detectors detecting a voltage at a point between the converter and power system, a current output from the converter and effective power from the voltage value and a current value detected, units computing an angular frequency of the voltage output from the converter, based on an effective power value and an output target value of effective power and an output voltage target value of the converter, based on a current value, a set voltage value and an angular frequency, and a controller controlling the converter according to the output voltage target value.

Abstract: According to one embodiment, a system includes modules to detect a node voltage and an output current of a converter, a detector to obtain an effective power value, a system condition detector to detect a power supply condition in the electric system or the operating conditions of devices included in the electric system and then output a first signal, a setting unit to switch a set value to a preset first or second value and then output the set value, a unit to calculate an angular frequency of an output voltage of the converter on the basis of an output of the detector, the value, and an output of the system condition detector, and a unit to calculate a target value of the converter.

Abstract: According to one embodiment, the photovoltaic system includes a memory configured to store power generator characteristics to be applied to the photovoltaic system, a calculation section configured to calculate an output target value to be output by the photovoltaic system using the power generator characteristics read from the memory, an operation target value, system data of a power system, and output data from the photovoltaic system to the power system, and a photovoltaic section configured to supply a corresponding power to the power system based on the output target value calculated by the calculation section.

Abstract: A power system stabilizing device includes an arithmetic unit that constructs a system model by collecting various kinds of system information, calculates a transient stability under an assumed accident condition beforehand, and selects, for each assumed accident in advance, a target solar power generator for shutdown and a target power generator to be disconnected to stabilize a power system, and a control unit that shutdowns the shutdown target solar power generator and disconnects the disconnection target power generator from the power system which are selected by the arithmetic unit when a system accident occurs.

Abstract: An energy management system of an embodiment includes first and second registration processors, first and second receivers, an aggregation processor, first and second transmitters, and a proration processor. The first registration processor registers a first energy management system as a host system. The second registration processor registers a second energy management system as a slave system. The first receiver receives an amount of an energy supply and demand and an adjustable amount of an energy supply and demand. The aggregation processor aggregates the received amount of an energy supply and demand and the received adjustable amount of an energy supply and demand. The first transmitter transmits aggregated results. The second receiver receives an adjustment amount of an energy supply and demand. The proration processor prorates the received adjustment amount of an energy supply and demand. The second transmitter transmits individual adjustment amounts of a power supply and demand.

Abstract: A power supply system comprises: a second electric power converter that converts power discharged by electric power storage means to AC power and that converts charging power to the electric power storage means to DC power; a second current detector that detects the current that is output from the second electric power converter; an electric characteristic computation section that calculates the output current IGref and the electrical output torque Te of a virtual power generator, based on the voltage VT, angular frequency ? and voltage set value Vref of a first electric power converter and the second electric power converter, and their connection point (point a) with the power system; a rotor speed computation section.

Abstract: According to one embodiment, a system includes modules to detect a node voltage and an output current of a converter, a detector to obtain an effective power value, a system condition detector to detect a power supply condition in the electric system or the operating conditions of devices included in the electric system and then output a first signal, a setting unit to switch a set value to a preset first or second value and then output the set value, a unit to calculate an angular frequency of an output voltage of the converter on the basis of an output of the detector, the value, and an output of the system condition detector, and a unit to calculate a target value of the converter.

Abstract: According to one embodiment, a system includes a battery to charge power and discharge a direct-current power to a converter, the converter supplying the converted power to a power system, detectors detecting a voltage at a point between the converter and power system, a current output from the converter and effective power from the voltage value and a current value detected, units computing an angular frequency of the voltage output from the converter, based on an effective power value and an output target value of effective power and an output voltage target value of the converter, based on a current value, a set voltage value and an angular frequency, and a controller controlling the converter according to the output voltage target value.

Abstract: According to one embodiment, the photovoltaic system includes a memory configured to store power generator characteristics to be applied to the photovoltaic system, a calculation section configured to calculate an output target value to be output by the photovoltaic system using the power generator characteristics read from the memory, an operation target value, system data of a power system, and output data from the photovoltaic system to the power system, and a photovoltaic section configured to supply a corresponding power to the power system based on the output target value calculated by the calculation section.

Abstract: The present invention provides a communication network system having a central management device and a plurality of local area network systems. Each of the plurality of local area network systems has a router and a terminal. The central management device encrypts a common key by using each public key of each router, and sends the encrypted common key to each router. The router decrypts the encrypted common key sent from the central management device by using a secret key of the router. The router encrypts communication data to be sent from a terminal in the router's local area network system to a terminal in another local area network system, or to be sent from the router to the central management device by using the common key, and sends the encrypted communication data to another local area network or the central management device.

Abstract: A network system providing secure service facility has a central control & management equipment to enable unified key management. The network includes a plurality of switching equipment and central control & management equipment, each of which includes encryption section. The encryption section of central management & control equipment encrypts; (a) a public key of switching equipment of a called party (i.e. terminating switching equipment); and, (b) a common key for encrypting message to be transferred between switching equipment. This is carried out each time a call requesting secure communication is originated. Then, the encrypted keys are delivered to the switching equipment of a calling party (i.e. originating switching equipment). Central management & control equipment maintains public keys of any switching equipment in a database.

Abstract: The present invention provides a communication network system having a central management device and a plurality of local area network systems. Each of the plurality of local area network systems has a router and a terminal. The central management device encrypts a common key by using each public key of each router, and sends the encrypted common key to each router. The router decrypts the encrypted common key sent from the central management device by using a secret key of the router. The router encrypts communication data to be sent from a terminal in the router's local area network system to a terminal in another local area network system, or to be sent from the router to the central management device by using the common key, and sends the encrypted communication data to another local area network or the central management device.

Abstract: A telescopic rod antenna apparatus of the present invention includes a mechanism for extending/retracting a telescopic antenna element by operating a smallest-diameter one of rods of the antenna element, and a means for setting the rods in the second state where a tip portion of a largest-diameter rod contacts an O-shaped ring seal means and then extending the antenna element using the mechanism, setting the rods in the second state where the antenna element is retracted using the mechanism, and displacing the second state to the first state where the largest-diameter rod is returned to the initial position of a holding tube to bring a top portion into contact with the O-shaped ring seal means.

Abstract: A telescopic rod antenna according to the present invention includes an antenna element and a waterproof ring-shaped seal member which is inserted in a ring-shaped gap in a joint between two rods of the antenna element. The ring-shaped seal member is obtained by shaping a thermoplastic resin film strip, on which at least one projecting portion is formed in its longitudinal direction, like a ring and compressing and inserting a ring-shaped film into the ring-shaped gap. A plurality of ring-shaped contact portions are formed on both sides of the film strip in its longitudinal direction while the projecting portion of the film strip serves as a basic contact portion. The ring-shaped contact portions are adhered to the inner surface of the larger-diameter rod and the outer surface of the smaller-diameter rod at a predetermined pressure.

Abstract: A multi-stage telescopic antenna for use in vehicles and a method for manufacturing such an antenna in which the antenna element, which comprises uppermost rod and conductive pipes, is free of any bending or breaking damage even if a large load is applied to the antenna element from a lateral direction, and there is no permanent deformation occurs even after the load is removed, so that the antenna element can always be maintained straight and smooth and stable extension and retraction can be executed.At least the conductive pipes 12 through 14 are formed from a high-elasticity material obtained by heat-treating SUS 631. In the heat treatment, the material is heated at a standard temperature of 480.degree. C..+-.5.degree. C. and then gradually cooled.

Abstract: An electric extensible car antenna including an antenna element support cylinder detachably mounted to a cylindrical support member of an antenna attachment base from the outside of a car body; a single small-diameter rod antenna element inserted in an antenna element insertion hole of the support cylinder so as to be in contact with a conductive contact element; the proximal part of the antenna element led toward the proximal end of the support cylinder being guided in a direction by an antenna element guiding tube; and an antenna element extended and retracted by a rack-equipped flexible rope connected to the antenna element via an electric mechanism. It is desirable that the antenna element be made of an ultra-flexible material and that the support cylinder is made of a plurality of separate cylindrical units.

Abstract: A drive control apparatus for an electrically-driven type extensible/retractable antenna comprises a control circuit connected to a power supply, a motor controllable by the control circuit to be rotated in a normal or a reverse direction, a multi-threaded type worm provided on an output shaft of the motor, a worm wheel engaging with the worm, a drive gear receiving a rotational force of the worm wheel to allow it to be rotatably driven, a drive rope having a rack in mesh with the drive gear and adapted to be moved in a longitudinal direction upon the rotation of the drive gear, an extensible/retractable antenna element driven by the drive rope to allow it to be extended or retracted, stopper means for mechanically stopping an extending or a retracting motion of the antenna element when the antenna element reaches an extension or a retraction limit, a shock absorber made up principally of an elastic member for alleviating an impact force by which the antenna element is stopped upon collision with the stopper