Abstract: A machine tool includes a spindle headstock having a main spindle, a spindle headstock having a main spindle with a Z3 axis parallel to an axis center direction of the main spindle, a turret that moves relative to the spindle headstocks, and a controller that superposition-controls the spindle headstock with movement of the turret as a standard, wherein the turret is movable in directions of an X axis and a Ys axis that are orthogonal to a Z axis and intersect with the Z axis at an angle except for the right angle, and the controller moves the turret in a direction of a Y axis different from the Ys axis and the X axis by combining movement in the direction of the Ys axis and movement in the direction of the Y axis, and regulates, in the superposition control, the movement of the spindle headstock in the X axis direction associated with the movement in the Y axis direction.

Abstract: A machine tool includes a spindle headstock having a main spindle, a spindle headstock having a main spindle with a Z3 axis parallel to an axis center direction of the main spindle, a turret that moves relative to the spindle headstocks, and a controller that superposition-controls the spindle headstock with movement of the turret as a standard, wherein the turret is movable in directions of an X axis and a Ys axis that are orthogonal to a Z axis and intersect with the Z axis at an angle except for the right angle, and the controller moves the turret in a direction of a Y axis different from the Ys axis and the X axis by combining movement in the direction of the Ys axis and movement in the direction of the Y axis, and regulates, in the superposition control, the movement of the spindle headstock in the X axis direction associated with the movement in the Y axis direction.

Abstract: A simple machine tool including a relatively simple shaped turret having as many tool attachment parts as possible even when a cutout part for a movement path for a main spindle is provided. A machine tool includes a first main spindle, a second main spindle, a first turret having tool attachment parts, a second turret having tool attachment parts, and a controller having an indexing device. An edge of a cutout part formed in the second turret is a straight line in a direction crossing each side of a regular dodecagon centered at a turning center of the second turret, as seen in a Z axis direction, and each tool attachment part is disposed according to each side left in the regular dodecagon cut off by the cutout part.

Abstract: A simple machine tool including a relatively simple shaped turret having as many tool attachment parts as possible even when a cutout part for a movement path for a main spindle is provided. A machine tool includes a first main spindle, a second main spindle, a first turret having tool attachment parts, a second turret having tool attachment parts, and a controller having an indexing device. An edge of a cutout part formed in the second turret is a straight line in a direction crossing each side of a regular dodecagon centered at a turning center of the second turret, as seen in a Z axis direction, and each tool attachment part is disposed according to each side left in the regular dodecagon cut off by the cutout part.

Abstract: A protective relay system detects a first electric variable and a second electric variable of a power system to discriminate in a time series whether or not a fault portion of a line or equipment included in the power system exists within a predetermined range, so as to determine whether protection of the power system should be carried out. The system includes a digital filter for outputting a first difference electric variable data indicative of a difference between at least two sample data of plural sampling data of the first electric variable and a difference between at least two sample data of plural sample data of the second electric variable at plural sampling times of the time series. The system also includes an addition filter for outputting first and second additive electric variable data indicative of orthogonal vector data with respect to the first and second difference electric variable data.

Abstract: According to a method of this invention, information and check bits in one frame of information to be transmitted are divided into two fields (i.e., a first field not requiring addition of fixed bits, and a second field requiring addition of fixed bits). The characteristic inherent to the bit pattern formed of a sync signal and the second field does not appear in the first field so that the sync signal can be discriminated. The number of fixed bits inserted in one frame can thus be decreased, and transmission efficiency can be improved.

Abstract: In a digital protective relay system for protecting an electric power system, a first digital operation device receives digital data on the electrical quantities of the power system and performs an operation on the digital data to produce an intermediate result, which is then stored in a memory unit. A second digital operation device reads the intermediate result from the memory unit and performs an operation on the intermediate result to produce a final result. The memory unit is so connected as to permit writing by the first operation device only, and to permit reading by the second operation device only.

Abstract: A voltage/frequency converter is formed of a V/F converter circuit which converts an input potential into a frequency corresponding to the instantaneous value of the input potential, and a difference detection circuit which generates an output corresponding to the difference between the output frequency of the V/F converter circuit and a predetermined reference frequency. The V/F converter circuit is controlled according to the level of the output from the difference detection circuit, thereby reducing the deviation of the output frequency of said V/F converter circuit from the reference frequency.

Abstract: In a protective relay system for an electric power system having two terminals at which electrical quantity is sampled in synchronism with a clock signal produced at each terminal, and the sampled electrical quantity data are exchanged for protection at said opposite terminal: a synchronous signal is transmitted from each terminal toward the opposite terminal; time data T1 is transmitted from a first terminal SS2 toward a second terminal SS1, the time data T1 indicating a time point t.sub.1 of the transmission of the synchronous signal toward the second terminal SS1 with reference to the clock signal; the time data T0 is transmitted from the second terminal SS1 toward the first terminal SS2, subsequent to reception of the synchronous signal from the first terminal SS2, the time data T0 indicating a valuet.sub.0 -T1+t.sub.2where t.sub.

Abstract: In direction identification for a close-in fault when the voltage becomes very small, direction of the fault is determined from the discriminant D given by:D=V.sub.k1 i.sub.k2 -V.sub.k3 i.sub.k4where V.sub.k1, V.sub.k3 represent sample values of the voltage at time points k1, k3, and i.sub.k2, i.sub.k4 represent either sample values of the current at time points k2, k4 or such sample values minimum current component values corresponding to pre-fault power flow. Here, k1=n-m-M; k2=n; k3=n-m; k4=n-M, where m represents the number of sampling operations over an interval equal to a multiple of half cycle of the system frequency, M represents an integer, and n represents a sampling time point. A signal for use, e.g., as a condition for tripping a circuit breaker is produced when the fault is found to be in the direction of the protection zone.

Abstract: In a machine implemented method and a system for protecting an electric power system, a differential equationv=L(di/dt)+Riis solved by using an approximation ##EQU1## to determine the inductance L and to measure or discriminate the distance from the determined inductance, wherev represents the voltage,i represents the current,R represents the resistance,t represents the time,t.sub.k and t.sub.k-1 represent time points,i.sub.k+p and i.sub.k-p-1 represent values of the current i for time points represented by t.sub.k+p and t.sub.k-p-1,p represents integers (0, 1, . . . N),N represents a natural number,K.sub.p (p=0, 1, . . . N) represents constants, with at least K.sub.0 and K.sub.1 being values other than zero and being so determined that the errors in the approximation for the inductance is zero for specified frequencies.

Abstract: A protective relay system for protecting a power system includes a selection circuit, a comparing circuit, and a data processing unit. The selection circuit time-sequentially switches a plurality of input signals having electrical quantities from the power system under control of the data processing unit and applies the input signals to the comparing circuit. The comparing circuit applies to the data processing unit a discriminated output signal representing the result of the comparing of a level of a signal having an electrical quantity and obtained from the input signals to the comparing circuit with a reference level. At a time point upon lapse of a time corresponding to an electrical angle of 90.degree.

Abstract: In a protective relay system for an electric power system with relay devices at respective terminals, a synchronous signal is transmitted from each terminal upon occurrence of a fixed time relation with the clock signal subsequent to receipt of a synchronous signal from the opposite terminal. The synchronous signal is associated with time data indicating the relative time of receipt of the synchronous signal with reference to the occurrence of the clock signal. The time deviation of occurrence of the clock signal at each terminal with reference to occurrence of the clock signal at the opposite terminal is detected in accordance with the time data transmitted from the opposite terminal, the time point at which the synchronous signal from the opposite terminal is received, the time point at which the preceding transmission of the synchronous signal toward the opposite terminal took place and the clock signal at each terminal, and is used for phase-adjustment of the clock signal at each terminal.

Abstract: A protective relaying system is disclosed which includes a selection circuit for receiving a plurality of input signals from a power system and for selecting one of the input signals to provide a selected input signal. The system also includes a comparison circuit connected to the selection circuit for receiving the selected input signal, comparing the selected input signal with a predetermined reference signal, and producing a decision signal according to the result of the comparison. The system further includes a processing unit connected to the comparison circuit for receiving the decision signal and processing the decision signal to produce a relay output signal.

Abstract: Digital setting value data, having been stored in a first non-volatile memory in response to the operation of a first switch, is transferred to and memorized in a second non-volatile memory. Stored setting value data is read out from at least one of the first and second memories under the control of an address control circuit and coupled to a digital processing section for carrying out digital arithmetic processing for protective control in the processor.

Abstract: In data processing apparatus in which address and data are transferred by means of DMA through an address bus and a data bus, a coincidence circuit determines whether the address on the address bus coincides with an address designated by an address designation device, a latch circuit latches the data on the data bus when the coincidence is detected and stores the latched data, and an indicating device indicates the data stored in the latch circuit.

Abstract: An input setting method for a protective relaying apparatus including an input setting switch for setting data, a digital operational device for carrying out a relaying operation utilizing the data, and a memory device for storing the data, the method comprising the steps of setting the data by the input setting switch, storing the data thus set in the memory device, comparing the set data with the stored data, carrying out the relaying operation utilizing the data when the compared data are found equal, and issuing an alarm signal when the compared data are found to be unequal.

Abstract: In a digital protective relaying device utilizing a microcomputer for protecting an electric power transmission system, a setting switch is provided for writing the values into the computer after the relaying operation of the protective device is locked by a locking means. The protective values thus set in the computer is indicated on an indicating device under the control of the computer and visually checked by an operator, while the computer always confirming the coincidence of the set values with the indicated values.

Abstract: In a protective relaying apparatus for an electric power transmission system and the like there is provided a nonvolatile memory device in which various values required for protection of the system are written electrically. An input device designates addresses in the memory device and memorizes values in the addresses under control of a control device. A digital processing device carries out the protective operations for the electric power transmission system based on the values thus set in the non-volatile memory device.

Abstract: A fault component current is obtained in response to a fault at a fault point within a protective section on a transmission line at one end of the protective section. Assuming that a phase difference between the fault component current and a fault point current flowing through the fault point is known, the fault point current is obtained on the basis of the fault component current and the phase difference. Then, a voltage at an assumed fault point is obtained by using voltage and current at the one end of the protective section and the line constants of the protective section. An assumed fault point is then obtained to permit the voltage at the assumed fault point to be in phase with the fault point current. The assumed fault point is assumed to be a true fault point.