Showing papers on "Relay published in 1986"

An Expert System for Fault Section Estimation Using Information from Protective Relays and Circuit Breakers

Abstract: This paper deals with an expert system which can estimate possible fault sections using information from protective relays and circuit breakers. This system is applicable to dispatching centers and can help dispatchers to judge emergency situations as the first step in restoration procedures. When some faults occur, the system makes inferences based on both knowledge about protection systems and information on the operating protective relays and tripped circuit breakers. The system can give possible answers even in the case of multiple faults and false operations of relays and circuit breakers. This expert system is written in Prolog.

A Multi-Microprocessor Based Travelling Wave Relay - Theory and Realization

Abstract: A new travelling wave digital protection scheme to be used as an ultra high speed (UHS) EHV/ UHV transmission line relay is presented in this paper. Some of the potential problems and limitations associated with other travelling wave schemes are avoided. Verification of the relay operating principles is presented through digital computer numerical simulation using an electromagnetic transients program (EMTP) in conjunction with simulation of the proposed algorithm. Parallel digital processing is incorporated through multi-microprocessor implementation. Hardware and software of a multiprocessor prototype are managed in a way to fit the algorithm requirements in as simple a construction as possible. The resulting scheme achieves significantly improved security and dependability, in addition to the main features: fault classification and UHS phase selection in selective-pole schemes with minimum communication between the protected ends.

Experience with the R-RDOT out-of-Step Relay

Abstract: A new out-of-step relaying concept has been previously reported. The concept involves augmaenting apparent resistance (R) measurement with rate-of-change of apparent resistance (Rdot) computation. The new R-Rdot relay thus has more intelligence for control decisions. This follow-up paper presents the following new information: large scale simulation results, including use of relay outputs for discrete supplemental control action; additional details on design and testing of the microprocessor based relay; and experience during an extensive monitoring period at Malin Substation on the Pacific AC Intertie. The relay is now energized for initiating controlled separations at several locations within the Western North American Power System.

Point of purchase advertising system

Abstract: A point of purchase advertising system is provided which senses the presence of a person in the vicinity of an advertising display and thereupon renders an appropriate advertisement such as a recorded verbal message or a visual or aural demonstration. In preferred forms, the overall apparatus includes an ultrasonic sensing circuit for detecting the approach of a potential customer, an advertisement giving device, typically an endless tape playback unit and a coupled speaker, and a controller for operation of the playback unit in response to detection of a customer. A voice operated relay circuit is advantageously coupled with the audio output of the playback unit and the playback controller, so that operation of the playback unit is maintained until the entire recorded advertisement has been given.

Method and apparatus for controlling the operation of a DC load

Abstract: A control circuit and method for using the same in operating a power switch such as a relay, FET, etc., having conductive and nonconductive conditions and adapted to direct a high magnitude driving current from a power supply through an electric load circuit when the power switch is in the conductive condition. Such a power switch can be used to control small motors used extensively in motor vehicles. This control circuit comprises testing means for directing a low magnitude, low duty cycle testing current through the load or motor circuit while the power switch is in the nonconductive condition, sensing means for creating a control signal indicative of a predetermined electrical characteristic, such as current flow, in the load circuit, means for shifting the power switch into the conductive condition for energizing the load when the control signal from the sensing means has a predetermined value, i.e. exceeds a preselected level, and load protecting means for interrupting the high magnitude driving current passing through the load circuit when the driving current exceeds the preselected value. Preferably, the protective means involves no external resetting or time delay in operation.

Apparatus for controlling rotational speed of radiator fan

Abstract: A cooling system for a radiator in an internal combustion engine is provided with a pair of fans connected to a first motor for a small electric current and a second motor for a large electric current, respectively. Relays are provided for operating the first and/or second motor sequentially in accordance with the degree of cooling requirement of the engine. A delay device is provided for delaying the operation of the relay(s) for attaining a stronger cooling requirement for a predetermined short period just after the engine is started. A generation of rush current in the relay contacts is prevented.

Method for arc suppression in relay contacts

Abstract: In a circuit having an electro-mechanical relay, the contacts of which are subject to arcing, bridging across the electro-mechanical relay in a manner configured to begin conducting electrical current around the electro-mechanical relay prior to closing the electro-mechanical relay and to continue conducting electrical power around the electro-mechanical relay for a predetermined time after the onset of separation of contacts of the electro-mechanical relay pursuant to discontinuance of current flow through the electro-mechanical relay. An optical coupler is provided to ascertain a current flow through the relay coil effected to close the electro-mechanical relay contacts, and activates a shunt device in bridging electrical current flow around the electro-mechanical relay. The shunt device is provided to be substantially non-load carrying while the electro-mechanical relay is closed. Utility is found in protecting electro-mechanical relay contacts against damage due to arcing.

Relayed Communication via Consecutive-k-out-of-n: F System

Abstract: A special communication system with moving relay stations is introduced in this paper. The relay stations are all moving at the same speed from an origin toward a destination. If k consecutive stations fail before the first station reaches the destination, all stations ahead of the k failed stations as well as the k failed stations are lost. The objective is to have one station reach the destination without k or more consecutive failed stations between the destination and the origin. When the station reliability is known, a formula to compute the mean number of stations needed for the communication system is derived. An example demonstrates how the formula might be used to determine the optimal system configuration given a station's reliability and to judge the tradeoff between station reliability and the available budget for the communication system.

A New Approach to E.H.V. Direction Comparison Protection Using Digital Signal Processing Techniques

Abstract: Some problems concerning the performance of superimposed component directional relays are discussed, and it is shown that the basic directional criteria can be violated due to travelling wave phenomena or for fault occurrence approaching a voltage zero. A relay design is developed using digital signal processing techniques to overcome these problems. Tlhe complete relay is tested using a typical 40OkV transmission line application.

Hybrid electrical power controller

Abstract: A hybrid electrical power controller is provided with a relay having a coil and a pair of mechanical contacts. A solid state switching device is electrically connected in parallel with the mechanical contacts and the parallel combination of that switching device and the contacts is connected between an input and an output terminal. A relay coil energizing circuit is included and means is provided for producing a signal representative of current flowing in the relay coil following deenergization of the relay coil. A solid state switching device control circuit responds to this signal and turns off the switching device when the signals fall below a predetermined magnitude.

Transmission power control system in a satellite communication

Abstract: A satellite communication system between small earth stations through a satellite and a relay earth station. The relay earth station has a larger antenna and a higher power transmitter than those of a small earth station in order to regenerate received digital signals. The transmission power of the relay earth station is controlled according to rain attenuation between the satellite and the small earth station, and/or rain attenuation between the satellite and the relay earth station, so that rain attenuation is compensated by increasing the transmission power of the relay earth station.

Microprocessor-Based Overcurrent Relays

Abstract: Inverse overcurrent is normally associated with the overcurrent relay types, the operation time is inversely proportional (in certain degrees) with their overcurrent ratio.

Zero-current a.c. switching system

Abstract: A zero-current a.c. switching system is provided for controlling actuation of relay contacts between a power supply and a load. A primary switch selectively energizes the relay to maintain the relay contacts in the closed state. The load current flowing through the relay contacts to the load is sensed. A secondary switch responds to the sensed load current for normally conducting to energize the relay in parallel with the primary switch. The secondary switch ceases conducting each time the load current drops below a predetermined level to cease energizing the relay and open the relay contacts the next time the load current drops below the predetermined level following the opening of the primary switch.

Enhanced Algorithms for Transmission Protective Relay Coordination

Abstract: Algorithms employing sparse techniques for coordinating directional overcurrent and distance relays on transmission network are described with an example system. Analytical expressions are derived for determining the limiting values of settings for zones 2 and 3 of distance relays on systems with both two and three-terminal systems. These values are then used to completely coordinate all the three zones of distance relays and to ensure maximum coverage of the lines by these zones. Some of the desirable enhancements added to the existing overcurrent relay coordination algorithm have also been described.

Design and Testing of a Multi-Microprocessor Travelling Wave Relay

Abstract: This paper describes the design and testing of a digital ultra high speed (UHS) travelling wave based protective relay. It shows how a prototype has been realized by a simple and fairly low cost (a few hundred dollars for parts) dedicated multi-microprocessor system. The paper presents also the results of the tests carried out on the prototype by using a microprocessor based complex waveform signal generator (CWSG) which displays the output of a mainframe computer-based electromagnetic transients program (EMTP) in real time. The relay showed good practical behaviour, especially with regard to the UHS feature and faulted phase selection and fault classification capability.

Microwave relay station having a common standby channel for signals of different types of modulation

Abstract: A multichannel microwave relay station has first and second channels for respectively transmitting signals of different types of modulation, such as QAM and FM modulated signals. These different types of signal rely on a common standby transmission channel that is selectively capable of transmitting the different types of signals. The type of signal currently carried by the standby channel is automatically identified by a detector circuit, such as one that can automatically distinguish differences in the frequency spectrums of the different types of signals. A selecting circuit responds to the output of the detector circuit by selecting between first and second transmitting devices in the common channel, thereby dedicating it to the identified type of signal.

Backup system by radio equipment at important line is at fault

Abstract: PURPOSE:To transmit stably command talking to a terminal device at a fault of an important wired line by providing a switching function to a radio equipment to a master and terminal equipments at both ends of the important line. CONSTITUTION:If even one line is faulty among important lines 9, command line sections 21-23 of the master equipment detect it to activate internal relays L1-Ln of a wire/radio connector 3, contacts L connect the line 9 to a radio control equipment 5 and a signal is transmitted to the terminal device. On the other hand, when a line supervisory circuit 41 in a loudspeaker controller 4 at the terminal device detect a line fault, a relay 42 is activated to receive information from a radio receiver 6. When a radio wave transmitted from the control equipment 5 of the master equipment reaches the receiver 6, a switch in the receiver 6 is turned on, a relay 43 in the controller 4 is activated and a contact 431 switches the talking line to a loudspeaker amplifier 7 from the wired side to the radio receiver 6 and a contact 432 starts the amplifier 7 to give command information.

Device for opening and closing a vehicle top

Abstract: A device for opening and closing a vehicle top by rotations of drive shafts rotatably provided with both right and left sides of the vehicle, comprises two individual motors which actuate the individual drive shafts through speed reduction mechanisms, switching relays which switch the direction of rotation of both said motors respectively, switching relay actuation transistors which individually actuate both the switching relays, top-open and top-close command switches which command the opening and closing of said vehicle top, a switch command determination means which ascertains whether the top-open or top-close command switches are operated, an actuation means which conducts the top opening or closing by actuation of said switching relays via said switching relay actuation transistors on the basis of a signal from the switch command determination means when the top-open or top-close command switches are operated, rotation synchronization sensors which are possessed by at least one of the two motors and generate a pulse synchronized to the rotation of the motor, and a rotation synchronization correction means which synchronizes the rotation speed of both the motors when the pulses are fedback via the rotation synchronization sensor as the rotation speed of one of the two motors drops.

Piezoelectric relay switching circuit

Abstract: To control the operation of a piezoelectric relay, control circuitry is disclosed for direct ohmic connection to a utility AC source to draw the minimal power required to actuate the relay's bimorph member pursuant to selectively switching power current through either one of two separate loads. The control circuitry, which is largely implimented in a single integrated circuit chip, utilizes isolating resistance and the capacitances of a voltage doubler circuit and the piezoceramic plate elements for transient suppression and circuit protection.

Detection device for contact fusion in an electromagnetic contactor

Abstract: A detection device for contact fusion in an electromagnetic contactor in which an electric motor is connected by way of main contact of an electromagnetic contactor on the secondary side of a breaker equipped with electronic tripping device has a detection circuit for the voltage applied to the electromagnetic contactor coil connected in series with a pushbutton switch and a detection circuit for the voltage applied to the electric motor; a relay coil of a relay for detecting the contact fusion is connected to the tripping coil of the breaker and an ON-OFF element for supplying or interrupting the supply of an electrical current to the coil and a control circuit for the ON-OFF element are connected to the detection circuit for the voltage of the electrical motor both of the detection circuits are coupled with each other by a photocoupler, whereby the ON-OFF element is turned ON when the pushbutton switch is turned OFF in the case of the fusion of the main contacts, thereby exciting the relay coil to turn the detection relay for contact fusion to ON, by which the tripping coil is excited to trip the breaker so as to interrupt the operation of the electric motor.

Light-sensitive switch structure and method with inverse off/on ratio

Abstract: Light-sensitive switch structure for and method of turning a street light, or other load, on or off in response to varying light levels. The switch is designed to recognize the daily variations in light level and is capable of switching a load off at a light level lower than that at which the load is switched on. In a preferred embodiment the switch consists of a photo-sensitive element, two relays with time delay features, and two current limiting resistors to regulate the current flowing through the operating coils of the relays. In other embodiments wherein the values of the circuit components are properly selected one of the resistors regulating the current flowing through the operating coils of the relays may be eliminated. In accordance with the method of the invention one of the relays operates contacts which energize or de-energize the load, while the other relay operates contacts which connect or disconnect the resistors to or from the operating coils of the relays. The resistors function in concert with the varying resistance of the photo-sensitive element to provide the desired operation of the relays to effect the desired energizing of the load with an inverse light level ratio.

Method and means for preventing theft of a powered means of transportation

Abstract: A method for preventing theft of a motor-driven means of conveyance such as a car, motorcycle, boat etc, by which at least one relay (13, 113) is used for breaking an electrical circuit for starting the motor According to the invention the relay (13, 113) is connected to the electrical circuit immediately adjacent one of the poles of a battery (1) or alternatively immediately adjacent a spark plug (119), and furthermore the battery pole, alternatively the spark plug (119), is encased together with the relay (13, 113) in order to make it impossible to by-pass the relay (13, 113) The invention also relates to a device for preventing theft of motor-driven means of conveyance

Signal distribution system hybrid relay controller/driver

Abstract: A hybrid controller is used to control a plurality of relays, within a switching matrix, for effecting connection of an equipment under test to at least one of a plurality of test instruments. To do so, the hybrid controller utilizes latch drivers which are capable of driving 24 relays simultaneously. To check whether or not the correct relay is activated, drivers are used to sense the statuses of the relays and forward the information to a central processing unit for comparison. The drivers are controllably actuated by a decoder means, which in turn is controlled by the central processor.

Mobile radio communication system

Abstract: PURPOSE:To attain smooth mobile radio communication by bringing a transmitter for a relay station into the transmission state by a reference station when transmission is started and bringing a transmitter for a mobile station into the transmission state after a timer set time. CONSTITUTION:When transmission start is given to terminals 8, 17 of the reference station, transmission start is given to the mobile station transmitter 4 and the relay station transmitter 13 via controller connection sections 5, 14, and a radio wave is irradiated from a mobile station antenna 1 and a relay station antenna 10 via antenna switching sections 2, 11. The radio wave is received by a reference station antenna 18 at the relay station and enters a receiver through an antenna switching section 19. A relay control section 22 uses reception information from the receiver 20 to apply transmission start to a mobile station transmitter 24, and a radio wave is irradiated from a mobile station antenna 26 to the mobile station via a switch section 25. Since a difference is given to the transmission start time between the transmitters 4 and 24 through the operation above, a timer 9 is applied when an input is given to the terminal 8 to retard the start of transmission for a prescribed time thereby making the transmission start identical to the transmitters 4 and 24.

Centralized switching circuit for building electrical network

Abstract: In a building electrical network including a power circuit constituted by several loops connected to sockets, lamps 35, 36, 37 and/or other electrically-operated apparatus, and a low-voltage circuit constituted by several loops connected to control means or sensors 38, 39, 40, 41 for controlling the loops of the power circuit, each loop of the low-voltage circuit and the corresponding loop of the power circuit are interconnected through a removable switching module 16 located in a centralized switching block 5. The low-voltage loops are not directly connected to terminals 12, 14 of the switching block, but are connected to terminals 45, 47 of a terminal strip 6, jumpers 46 establishing the connection between the terminals of the terminal strip(s) 6 and the terminals 12, 14 of the switching block 5. The plug-in switching modules 16 include an electronic relay member 21 (e.g. an optocoupler) and a power circuit switching component 23 which may perform various functions (remote ON/OFF, remote dimming, timing, etc.).

Device for self-monitoring of relay contacts

Abstract: The invention relates to a device for self-monitoring of relay contacts, the switching contacts (2, 4) of a first relay (1) and of a second, redundant relay (3) being connected in series in such a manner that, when the first and second relays (1, 3) are energised (or deenergised), they close a circuit (A, B) which contains a drive element or a control unit The first and second relays (1, 3) are provided such that the switching contacts (2, 4) close a further circuit when the first and second relays (1, 3) are in the deenergised (or energised) state and the switching contacts (2, 4) are in the tripped (or pulled-in) state, in which further circuit a voltage source (5) and a signal transmitter (6) are connected in series

Solid state railroad lights/gate controller

Abstract: A railroad crossing lights/gate controller for effecting operation of the crossing lights and lowering of the crossing gate during normal train operating conditions and during a gate controller failure mode includes a train sensing input, a gate control circuit, a lights control circuit, a solid state logic and monitor circuit and a fail/safe relay. The train sensing input provides one signal condition when the approach of a train is sensed and another signal condition when no train is sensed. This input is connected to the solid state logic and monitor circuit which is also connected to the gate control circuit and the lights control circuit. The gate control circuit has power applied thereto to maintain the gate in a raised position when the train sensing input indicates a no train condition and the lights control circuit has power supplied thereto to operate the lights in a flashing condition when the train sensing input indicates the approach of a train. The logic and monitor circuit applies and removes power to the gate and lights control circuit in accordance with the signals at the input. The fail/safe relay is connected to the logic and monitor circuit and to the gate and lights control circuits to automatically remove power to the gate control circuit and apply power to operate the lights in the event no power is applied thereto. The logic and monitor circuit further senses the application of power to the gate control circuit and to the lights control circuit and removes power to the fail/safe relay under certain sensed conditions.

Dual mode controller for assigning operating priority of two loads

Abstract: A dual mode controller used to allow only one of either a primary heating/cooling system or a hot water heater to operate at one time. It is particularly useful where utility billing is based on peak demand. A two-position switch is used to select the mode such that in one switch position the heating/cooling system is given priority regardless of the operating status of the hot water heater, and in the other position the operating load is given priority. This relatively simple circuit includes one conventional relay and either another conventional relay or a pilot duty relay energized by an integral "doughnut" type current transformer.

Signalling method and device for bidirectional digital transmission link

Abstract: A method of transmitting signalling along a bidirectional digital transmission link consists in transmitting from an intermediate equipment of the link a signalling message in two parts. One is a characterizing part the form of which depends on the signalling type and which is substituted for data of one of the digital bit streams carried by the link in the direction from one of the terminals referred to as the processing terminal. The other is a localizing part whose form is independent of the signalling type and which is substituted for data of the digital bit stream carried by the link in the direction towards the other, so-called relay terminal. The relay terminal responds by sending an acknowledgement message to the processing terminal, the time-delay of this relative to the characterizing part being used to identify the sending equipment. A signalling message transmission circuit controls switching circuits inserted into the paths of the digital bit streams carried by the link. The equipment for transmitting signalling along a bidirectional digital transmission link comprises a clock circuit defining in terms of the period of its output signal the duration of a signalling message characterizing part. Its half-period defines the duration of a localizing part. There is also a circuit for selecting the first complete period of the clock circuit output signal after a signalling transmission request, as well as circuits for composing the two parts of the message.

Static switch circuit or device for the protected supply of a load, and its line

Abstract: Each phase circuit comprises a static switch of the IGT or GTO type, between the anode and the cathode of which there is arranged in parallel a series mounting of a CTP resistance and of a normally open switch which is closed when a current detector detects a short abnormal intensity lower than six times the rated current; said static switch is locked either immediately when the rate is higher than six, or with a short delay on the contrary. Said device is particularly convenient to be used in industrial installations where it is desired to replace the associations of contactors, thermal relay and circuit breaker by static apparatuses.