Abstract: An apparatus and method to identify a harmonic producing load on a utility electrical network is described. The apparatus is connected to the utility electrical network at a location adjacent to a load. The apparatus includes a network voltage node to receive a voltage signal, and a network current node to receive a current signal. The apparatus also includes harmonic filters to process the voltage signal and current signal to isolate selected harmonic voltage signals and selected harmonic current signals. A signal processor derives a set of selected power signals from the selected harmonic voltage signals and the selected harmonic current signals. The signal processor also identifies any positive polarity signals in the set of selected power signals. In response to a positive polarity signal, the signal processor activates a sensory output device to indicate that harmonics are being produced by the load.

Abstract: A circuit is provided for generating a current that is a harmonic of the frequency of the utility system and which is of a selected amplitude and phase to reduce the total harmonic distortion of a system that converts alternating current to direct current, or vice versa. The DC signal is sampled and by controlling switches, a sinusoidal current at the desired harmonic is generated, and is provided to a neutral of a transformer that injects this current into the multiphase AC system used by the utility in a very low cost, easily controlled, and highly effective manner. In a second embodiment, the injection current is provided to a common junction of a magnetic device.

Abstract: An active filter device simple in construction and low in price in which higher harmonic components can be stably suppressed without requiring a passive filter even when a load to be compensated includes a capacitative load.

Abstract: A counter cell includes a latch circuit, control circuit, and a pull-up circuit. The latch circuit is formed of a first clocked half-latch, a second clocked half-latch and an inverter for storing a binary output signal. The first clocked half-latch is responsive to a first clock phase signal for transferring the binary output signal from its input to its output. The second clocked half-latch is responsive to a second clock phase signal for transferring a binary output signal from its input to its output. The control circuit is responsive to an input complement signal for selectively passing the first clock phase signal to the first clocked half-latch so as to permit toggling the state of the binary output signal. The control circuit requires only one transistor and two input signals to perform its required functions. When the input complement signal is High and the first phase input clock signal is High, an enable signal is sent to the first clocked half-latch, thereby enabling the count process.

Abstract: An active filter and method for stabilizing a single-phase ac line to which multiple nonlinear loads are connected, comprises two pairs of switches connected in two switching loops across a capacitor. One loop is connected to one leg of the line through an inductor and the other loop is connected to the other leg of the line directly. Voltage from the capacitor is followed and averaged to produce a scaling factor which is multiplied by a value corresponding to the actual ac line voltage. The resulting trajectory for the line current is compared to the actual line current and used to switch the pair of switches in the first loop to shape of the line current. A zero-crossing detector connected to receive the ac line voltage determines the polarity of the shaped current.

Abstract: A device for disabling a motor vehicle having an engine, an engine compartment, a hood, a primary circuit enabling the operation of the engine and a power source. The device includes a remote receiver having a pair of remote controlled switches which are controlled between contact and open positions by a remote transmitter. The device connects one of the switches with a primary circuit with the switch normally in a contact position maintaining the power circuit normally complete. A secondary electrical circuit which controls electrically actuated hood locks is also provided. Second switches of the remote receiver are connected in the secondary circuit with the second switches being normally open which maintains the secondary circuit normally broken.

Abstract: A bias voltage vectorially added to the controllable voltage injected in series with the line voltage of a transmission line reduces the required MVA rating for a unified power flow controller (UPFC) in applications where the power in the transmission line only flows in a single direction, or where the range of the transmission angle is otherwise unequal about zero.

Abstract: A power line conditioner includes an active filter coupled, in series, and a passive filter coupled, in parallel, to a three-phase power distribution network. The three-phase power distribution network includes a voltage source that induces three-phase input currents at a first end of the three-phase power distribution network. A load, circulating three-phase load currents, is positioned at a second end of the three-phase power distribution network. The active filter controller of the invention uses synchronous transformations to identify selected harmonic reference components corresponding to individual harmonics of the three-phase load currents. The selected harmonic reference components are multiplied by a predetermined factor corresponding to a permissible percentage of the individual harmonics that may be injected into the supply voltage. This results in active filter reference signal components that are applied to the active filter.

Abstract: A harmonic blocking converter system for converting power between an AC source and a DC source includes a harmonic blocking transformer and a converter which generates undesirable harmonic currents including fifth and seventh harmonic components. The harmonic blocking transformer includes a polyphase main transformer and a harmonic blocker coupled with wye and delta secondary windings of the main transformer, so as to substantially block passage of the fifth and seventh harmonic currents to the AC source. A waveform enhancer may couple the harmonic blocking transformer with the converter. The converter may be constructed for 2-level operation, or, with the addition of auxiliary diodes, for 3-level operation. Such a harmonic blocking transformer and a method of blocking undesirable harmonic currents are also provided.

Abstract: A harmonic blocking converter system for converting power between an AC source and a DC source includes a harmonic blocking transformer and a converter which generates undesirable harmonic currents including fifth and seventh harmonic components. The harmonic blocking transformer includes a polyphase main transformer and a harmonic blocker coupled with wye and delta secondary windings of the main transformer, so as to substantially block passage of the fifth and seventh harmonic currents to the AC source. A waveform enhancer may couple the harmonic blocking transformer with the converter. The converter may be constructed for 2-level operation, or, with the addition of auxiliary diodes, for 3-level operation. Such a harmonic blocking transformer and a method of blocking undesirable harmonic currents are also provided.

Abstract: A key and lock system is provided for enabling circuits of a vehicle. A key including a plurality of male contacts is inserted into a lock. Predetermined pairs of male contacts are connected to each other. A plurality of female contacts are arranged to receive the male contacts. Circuits of the automobile are connected to the female contacts. If a pair of male contacts is properly mated to a pair of female contacts circuits of the automobile are enabled. The lock can be reversed wire so that either side of the key can be inserted into the lock.

Abstract: An ignition switch of an automotive vehicle employs a non-contacting key reader for reading a code on a key when the key is inserted lengthwise into the switch. Such a key reader is either a magnetic one that reads a magnetically coded key or an optical one that reads an optically coded key. A detent mechanism defines successive Accessory and On (Ignition) positions as the key is increasingly inserted. Various branch circuits are switched on to the vehicle's electric power supply at these two positions provided that a valid key has been detected. Full insertion of the key physically pushes a spring-loaded plunger of a mechanical start switch at the inner end of the ignition switch, causing start switch actuation and the engine starter motor to crank the engine, provided that the key is valid. Once the engine starts, the key is released and is returned to the On position.

Abstract: A motor vehicle theft protection system employs a pre-set distortion in the vehicle timing system to preclude unauthorized access to the vehicle. The system uses a key containing codes corresponding to the timing off-set. Without the codes, the timing off-set prevents operation of the vehicle.

Abstract: A UPS device adapted for parallel connection to a load along with one or more other UPS devices, having circuitry for sharing of the load, including load harmonics. A feedback network has an error signal circuit which generates an error signal representative of the difference between the actual current provided by the device and the designated share of current it should provide. The error signal is transformed by a value representative of the effective output impedance of the UPS inverter, whereby the inverter is controlled to share the fundamental of the load current as well as the harmonics.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. Windings for each of the phases includes an in-phase coil connected between a common neutral and vector coils for each of the other two phases, the output windings thereby being phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core. The harmonic current filtering transformer may be used as part of a harmonic cancelling power system which includes multiple linear and nonlinear loads, and protective devices, switches, filters and other components on both the input and output sides of the transformer as in a conventional power system since the harmonic cancelling transformer does not require additional secondary windings or other electrical components previously thought necessary to achieve harmonic cancellation.

Abstract: An operator identification system utilizes "dead" switches, such as window actuating switches which have no control function until such time as a vehicle ignition is turned on, for identifying a particular vehicle operator. The inactive switch contact closure is detected by an electrical circuit which also tests to determine whether the ignition is off and if it is, the window switch closure provides an operator identification signal to a vehicle microprocessor for identifying a particular driver and preset option functions associated with that driver.

Abstract: An AC power line is monitored for currents and voltages at non-fundamental frequencies (including harmonics). A controlled active filter injects compensating current into the AC power line. The injected compensating current is responsive to both the sensed non-fundamental frequency current and to the sensed non-fundamental frequency voltage residing on the power line. In one embodiment, the controlled active filter comprises a transconductance amplifier which obtains its operating power from a controlled flow of power from the AC power line being monitored.

Abstract: An electrical power distribution system of an industrial plant or a commercial building and having a capacity for delivering at least 500 KVA, includes a voltage step-down transformer connected between an AC source of electrical energy and a pair of power distribution line conductors across which there is connected a pulsed inductive load, such as a motor with a thyrister speed controller. The power factor of the system is corrected by a power factor correction capacitor connected directly across the system power distribution line conductors. Pulsed inductive loads tend to excite large harmonic currents in such systems having both a transformer and a power factor correction capacitor directly across the distribution line conductors. A filter, made up of a filter capacitor and a filter inductor tuned exactly to one harmonic, are connected in a series circuit branch that is connected directly across the system power distribution line conductors.

Abstract: Series capacitor equipment for connection into an electric power line (A) has a capacitor bank (C) and a controllable inductor connection (L, T1, T2) connected in parallel therewith and comprising a series connection of an inductor (L) and a controllable semiconductor connection (T1, T2). Further, the equipment comprises control members (CU) adapted, on the occurrence of a subsynchronous resonance oscillation, to control the semiconductor connection with separate control angle values during positive and negative half-cycles of the capacitor voltage for generation of a subharmonic voltage which counteracts the resonance oscillation.

Abstract: An apparatus and method of constructing a sinusoidal output signal corresponding to a predetermined harmonic component of a sinusoidal input signal is described. The input signal is multiplied by a specified harmonic component of cosine and sine reference signals to divide it into direct and quadrature signals. The direct and quadrature signals are proportional to the amplitude of the specified harmonic component of the reference signals at the specified phase. Each cycle of the direct and quadrature signals is sampled a number of times to form direct and quadrature signal segments. The direct and quadrature signal segments are respectively placed in direct and quadrature circular buffers. Each circular buffer includes a number of formerly sampled segments. Before adding a new segment, the oldest segment in the buffer is dropped. Direct and quadrature amplitude sums, corresponding to the sum of all sampled segments within the respective circular buffers, are maintained.

Abstract: An improved active power line conditioner is disclosed. The active power line conditioner includes a series inverter coupled to an energy input source, and a parallel inverter coupled to a non-linear load. The non-linear load is powered by a three phase load current which includes fundamental components and harmonic components. An energy storage element is electrically connected between the series inverter and the parallel inverter. The series inverter is controlled by a series filter controller which performs synchronous transformations on the load current to generate a series filter feedforward signal corresponding to the fundamental components of the load current. The series filter feedforward signal is applied to the series inverter to generate sinusoidal input currents for the non-linear load.

Abstract: A compensating circuit arrangement for a power transmission system for rapidly inserting capacitance into a transmission line for desired portions of cycles of the operating frequency of the system, has first anti-parallel connected thyristors in series with a capacitance and second anti-parallel connected thyristors in parallel with the series connected first thyristors and the capacitance. A control responsive to a variable in the system, and related to system reactance, switches desired thyristors on at desired times during a cycle of operating frequency to introduce controlled amounts of capacitance into the power transmission system.

Abstract: An improved active power line conditioner is disclosed. The active power line conditioner includes a series inverter coupled to an energy input source, and a parallel inverter coupled to a non-linear load. The non-linear load is powered by a load current which includes fundamental components and harmonic components. An energy storage element is electrically connected between the series inverter and the parallel inverter. The parallel inverter is used for current control functions, while the series inverter is used for instantaneous output voltage regulation. In one embodiment of the invention, a parallel current limiter is used for the parallel inverter. The parallel current limiter is fixed to satisfy specified output voltage total harmonic distortion requirements or peak to rms output current ratios in the active power line conditioner. A series current limiter may be used for the series inverter.

Abstract: A novel active power line conditioner is disclosed. The apparatus includes a parallel inverter, with a dc-link, coupled to an output line. The parallel inverter is controlled by a parallel inverter controller which forces the parallel inverter to act as a variable capacitor or inductor. The parallel inverter controller identifies and feeds-forward a desired phase shift value between an active power line conditioner voltage output signal and an active power line conditioner voltage input signal. Utilization of the desired phase shift value results in voltage control of the dc-link of the parallel inverter. The parallel inverter controller also produces a tuning capacitance current reference signal which reduces voltage magnitude errors of the output voltage.

Abstract: An automatic voltage control circuit by using reactive power is disclosed. The circuit comprises a proportional integrator, a triangular wave generator, a comparing circuit having first and second comparators, an inventer, and a reactive power control circuit, wherein the proportional integrator proportionally integrates the differences between output voltages and a reference voltage, the triangular wave generator outputs first and second triangular waves with a difference of phase angle 90.degree., the comparing circuit compares the output from the proportional integrator with the first and second triangular waves, the inverter controls the effective power by the output from the first comparator, and the reactive power control circuit controls the reactive power due to the variations of the load in response to the output from the second comparator, so that the output voltage can be maintained stably regardless of the variations of the load.

Abstract: A circuit is provided for generating a current that is a harmonic of the frequency of the utility system and which is of a selected amplitude and phase to reduce the total harmonic distortion of a system that converts alternating current to direct current, or vice versa. The DC signal is sampled and by controlling switches, a sinusoidal current at the desired harmonic is generated, and is provided to impedance network that injects this current into the multiphase AC system used by the utility in a very low cost, easily controlled, and highly effective manner. The impedance network comprises a single inductor and capacitance connected in series through each of the phases of the utility, with the current signal having an amplitude that is selected to substantially eliminate harmonics which cause high distortion of the utility signal.

Abstract: An apparatus and method of constructing a sinusoidal output signal corresponding to a selected harmonic of a sinusoidal input signal is described. The input signal is deconstructed into direct and quadrature components by respectively multiplying it with a selected harmonic of cosine and sine reference signals. The direct and quadrature components contain orthogonal dc components corresponding to the direct and quadrature magnitudes of the input signal at the selected harmonic frequency. The generated direct and quadrature magnitude values are respectively applied to error amplifiers in accordance with the invention. The outputs of the error amplifiers are respectively multiplied by the selected harmonic component of the sine and cosine reference signals. This provides the proper phase values for the respective quadrature and direct processed signals at the selected harmonic frequency.

Abstract: First and second dc linked, preferably voltage sourced, inverters are connected to an electric power transmission line in shunt and in series, respectively, by coupling transformers. Firing of the GTO-thyristors of the first inverter is controlled to regulate reactive power on the transmission line and to supply real power requirements of the second inverter. The second inverter is controlled to inject into the transmission line in series a voltage which can be adjusted in magnitude and from zero through 360 degrees in phase with respect to the transmission line voltage to selectively adjust any one or more of transmission line voltage magnitude, transmission line impedance and transmission line voltage phase angle.

Abstract: A standby power supply system is provided for supplying normal AC power to a critical load from an AC power source during normal operating conditions, and for supplying emergency AC power to the load during failure of the AC power source. During normal operation, the standby power supply system actively neutralizes undesirable harmonic components in the input current drawn by the load. The standby power supply system includes a power conversion device having a DC side coupled to a back-up power source and an AC side in parallel with the load and the AC source. A harmonic distortion sensor senses a harmonic distortion current component of a load current drawn by the load during normal operating conditions. A controller is responsive to the harmonic distortion sensor for causing the power conversion device to produce a harmonics neutralizing current to substantially neutralize the harmonic distortion current component produced by the load.

Abstract: The electrical dampening circuit for dampening resonance of a power signal in a power distribution network, comprises a capacitor C, an inductance L connected in parallel to capacitor C, and a resistance R connected in series with capacitor C and inductance L, values of capacitor C and inductance L being calculated so that (2.pi.f).sup.2 LC=1, where f is frequency of the power signal. The value of R is calculated so that 3.sqroot.L/C <R<(2/3) .sqroot.L/C whereby dampening of resonance is obtained.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.

Abstract: A harmonic compensator comprises a transformer having low leakage reactance connected between a utility and a load and a signal generator which injects into the transformer a signal having a frequency which cancels undesirable higher order harmonics induced by the load. The low leakage reactance nature of the transformer permits injection of high frequency signals which restore the fundamental sine wave of the signal from the utility and thereby eliminates undesirable nonlinear harmonics which cause up-line disruptions. The low leakage reactance transformers may comprise a coaxial structure having a thin hollow tube as the primary coil, a coaxial structure having a single main coaxial cable distributed into several paralleled coaxial cables of smaller diameter, or a co-planar transformer structure having flat strip line conductors wrapped around a conventional core as the primary and secondary coils.

Abstract: Quasi-harmonic neutralized inverter systems are provided with interphase transformers connected in a waffle tree configuration and each having a pair of inputs for receiving staggered voltage waveforms, wherein the stagger angle of the voltage waveforms reduces a harmonic component of an output voltage on an output terminal of each interphase transformer. Inverters produce voltage waveforms at phase angles necessary to provide the required stagger angles at the inputs of the interphase transformers in a first stage of the waffle tree configuration. A method for quasi-harmonic neutralization of voltages in an inverter system is also provided, in which interphase transformers, each having a pair of inputs for receiving staggered voltage waveforms, are connected in a waffle tree configuration, such that the stagger angle of the voltage waveforms reduces a harmonic component of an output voltage on an output terminal of each interphase transformer.

Abstract: A standby power supply system is provided for supplying normal AC power to a critical load from an AC power source during normal operating conditions, and for supplying emergency AC power to the load during failure of the AC power source. During normal operation, the standby power supply system actively neutralizes undesirable harmonic components in the input current drawn by the load. The standby power supply system includes a power conversion device having a DC side coupled to a back-up power source and an AC side in parallel with the load and the AC source. A harmonic distortion sensor senses a harmonic distortion current component of a load current drawn by the load during normal operating conditions. A controller is responsive to the harmonic distortion sensor for causing the power conversion device to produce a harmonics neutralizing current to substantially neutralize the harmonic distortion current component produced by the load.

Abstract: A system and method is provided compensating utility distribution line transients such as voltage sags in a dynamic manner, by inserting a voltage signal in series with the distribution signal having a magnitude and phase to effectively cancel out the voltage deviation caused by a network disturbance. An energy storage device such as a storage capacitor is used to provide energy to an inverter circuit which is controlled to generate the series-inserted signal. Preferably a converter such as a chopper is utilized between the storage element and the inverter, to provide a constant dc input to the inverter. A controller generates a corrective error signal based upon the deviation between the utility supply voltage as affected by the disturbance, and the nominal ideal voltage signal, and adjusts the insertion voltage so as to optimize real power delivery to the utility distribution line.

Abstract: A circuit for correcting perturbations in a power system signal operating at a system line frequency includes a capacitor for drawing a capacitive current and a first inductor for drawing an inductive current substantially equal in amplitude and substantially one hundred eighty degrees out of phase with the capacitive current. The first inductor is connected in parallel with the capacitor to form a storage module for storing energy therein wherein the storage module is tuned to resonate at the system line frequency and wherein the storage module is connected in parallel across the load. A second inductor connected in series between a power source and the load isolates the power source from the load.

Abstract: A fault current surge bypassing and transitional impedance compensation system for preventing subsynchronous currents on electrical power lines, with parallel lines being protected from the clearing of transient faults. Capacitor banks serve as only a partial solution to the disturbances with transient faults during conventional recovery modes of operation. The fault current bypassing and impedance compensation system, coupled in series to each transmission line, clears a transmission line fault current and dynamically balances the inductor impedance on the transmission line after the fault mode clears when a return is made to the normal mode of operation. A circuit based solid-state switching power converter or "voltage-sourced inverter" with self-commutating GTO semiconductor switches is used, having all GTOs switched-on and maintained in this condition for the fault current to pass.

Abstract: A security system for an automobile starter system is an electrical installation on the automobile whereby the starter system of the automobile can be actuated only when a correct ignition key to the automobile is used. Also, the starter system is safeguarded from being mistakenly actuated as the automobile motor is running. Two types of electrical circuit configuration are proposed to perform the automobile starter system security functions. The first electrical circuit configuration utilizes the analog circuitries applied with voltage window detection concept. The other electrical circuit configuration utilizes the sequential digital circuitries applied with the signal code detection concept.

Abstract: A bicycle security system includes a locking bicycle rack and employs a user's automated teller banking card to operate the system and debit charges accrued in connection with use of the system from the user's bank account. The locking system has an electronic control means which locks and unlocks the bicycle rack by means of a banking card. The electronic control means includes a timer which tracks time in connection with use of the system. The control means thereafter calculates a charge based upon the use of the system and debits the accrued charges from the user's bank account via telephone modem. The locking bicycle rack incorporates three locking pins which lock the bicycle at the frame, the front wheel and the rear wheel to provide a high degree of security.

Abstract: A system for remotely disabling or enabling an automobile having at least one receiver that scans signal codes transmitted in frequencies dedicated to mobile telephone communications, and at least one frequency outside that used in mobile telephone communications. The signal codes received by the receiver are compared to an enabling code and a disabling code stored within a programmable memory. When the owner of an automobile finds the vehicle stolen, the owner dials the telephone number corresponding to the disabling code of the automobile. The dialed number causes a signal code to be transmitted from the mobile telephone transmitted network, wherein the signal code is received by the stolen automobile. If the transmitted signal code matches the programmed disabling code the automobile is disabled. Similarly, the automobile can be enabled if a signal code is received that matches the enabling code the automobile.

Abstract: A scheme for counteracting subsynchronous resonance in an AC power system that comprises a passive device in combination with a line inductive shunt reactor (L10). The device is connected from the neutral end (N) of the reactor (L10) to ground and comprises a plurality of circuit branches: one of those branches comprises a condenser (C10), another one includes an inductor (L12) in series with at least one tank circuit (C14, L14). The combination of these elements results in circuit paths from the AC line to ground of selected admittance values for at least one selected frequency as well as in a solid grounding of the shunt reactor neutral at synchronous frequency.

Abstract: An a.c. machine (7) with, connected in parallel thereto, a capacitor bank (CR, CS, CT), which are fed by a converter (1-4) with a d.c. intermediate circuit, form a resonant system which is excited by the rectangular current of an inverter (4) of the converter. In this case, there is superimposition of the fundamentals and the normal harmonics in the machine voltage and in the machine current of an additional harmonic with the frequency of the resonance point. In the lower speed range of the a.c. machine (7), this excitation is eliminated by an optimum operating sequence of current gaps, which are generated inside a current block by means of a quenching circuit (3). Current gaps are generated at the start and end of each current block for the purpose of damping the 11th and 13th harmonic, and in the middle of the current block for the purpose of damping the 7th harmonic. A turn-on angle basic value signal (.alpha..sub.M) is modified by a turn-on angle differential signal (.DELTA..alpha..sub.

Abstract: A subsynchronous resonance mitigation system, including a method and apparatus, for damping undesirable subsynchronous resonance oscillations in a generator, which, if left unchecked, may damage the shafts of a turbine-generator set. A remote coupling apparatus, such as a thyristor controlled series capacitor (TCSC) system, a sourced inverter device, or a static phase shifter, is coupled to the generator by a transmission line. In response to a firing command, the coupling apparatus introduces subsynchronous resonance mitigating currents into the transmission line. Sensors monitor power line parameters and/or the generator speed, and in response thereto, a higher-level controller generates a voltage command. A vernier controller responds to the monitored power line parameters and the voltage command to provide the firing command to the coupling apparatus.

Abstract: A circuit for correcting power factor and for reducing ac line current harmonic components in conjunction with bridge-connected capacitive-filtered loads and for providing a source of ac startup current for associated circuitry, for example a switch mode power supply which may form part of the load. The circuit comprises a rectifier bridge, a dual-tuned circuit having a tuned filter in series between an ac line input and the bridge, and a shunt capacitor across the input to the bridge. The tuned filter comprises a parallel connected inductor and capacitor, the shunt capacitor being tuned with the inductor to form a trap filter to reduce third-order and higher harmonic components in the ac line current. The circuit also includes a current source operatively connected to the shunt capacitor for providing a source of ac current immediately upon application of ac power to the ac line input.

Abstract: A circuit in a power system for suppressing an AC ripple superimposed on a bus signal on a bus includes a first circuit for producing first and second signals having a frequency substantially equal to the AC ripple frequency wherein the second signal is a phase quadrature of the first signal, a second circuit for combining these signals with a signal representing the bus signal having the AC ripple superimposed thereon so as to derive a control signal having substantially the same frequency and phase as the AC ripple, and a third circuit responsive to this control signal so as to substantially suppress the AC ripple on the bus.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.

Abstract: An air core inductor having mounted thereon a band of material of selected characteristics providing only an electromagnetically coupled resistance that reflects back into the windings of the inductor for filtering applications.

Abstract: A series impedance compensation system for a set of transmission lines which are used for electrical power transmission, with these parallel lines being protected from the transient faults and dynamic subsynchronous oscillation problems. These problems can become aggravated by the introduction of capacitor banks which thus serve as only a partial solution to the disturbances of transient faults during conventional recovery modes of operation. The impedance compensation system is coupled in series to each transmission line to dynamically balance the inductor impedance on the transmission line, responsive to demand, by injecting a voltage component determined to be optimized substantially at quadrature leading or lagging phase angles (.+-.90.degree.) with respect to the transmission line voltage and current components.

Abstract: An electrical system for bypassing the anti-theft system of a vehicle such that the engine can be started with a remote control. In particular, this is a system which allows the operator of a vehicle to start the vehicle from a remote location without having the key in the ignition and without alarming the vehicle's anti-theft device. Activation of the remote control which throws a switch, bypasses the normal key dependant ignition circuitry. A potentiometer in the bypass loop mimics the resistance pellet embedded in the ignition key, which is normally required for engaging the engine without alarming the anti-theft device. Other portions of an anti-theft system can also be bypassed if desired.

Abstract: A standby power supply system is provided for supplying normal AC power to a critical load from an AC power source during normal operating conditions, and for supplying emergency AC power to the load during failure of the AC power source. During normal operation, the standby power supply system actively neutralizes undesirable harmonic components in the input current drawn by the load. The standby power supply system includes a power conversion device having a DC side coupled to a back-up power source and an AC side in parallel with the load and the AC source. A harmonic distortion sensor senses a harmonic distortion current component of a load current drawn by the load during normal operating conditions. A controller is responsive to the harmonic distortion sensor for causing the power conversion device to produce a harmonics neutralizing current to substantially neutralize the harmonic distortion current component produced by the load.