49 results about "Digital protective relay" patented technology

The invention discloses a sampling value multi-interface synchronizing system based on IEEE1588, which is characterized by comprising a universal IEEE1588 clock interface and a universal multi-sampling value synchronizing interface, wherein the universal IEEE1588 clock interface is a communication receiving module provided with a plurality of IEEE1588 slave clock interfaces, and the number of theslave clocks can be automatically expanded according to the number of master clocks; and the universal multi-sampling value synchronizing interface is a communication interface which can form internetworking connection with merging units and comprises an Ethernet data receiving module, a software sampling and interpolating module, a phase-locked loop (PLL) module, a frequency tracking module and a multi-interface sampling value synchronizing module. The system of the invention can be used for electronic equipment requiring sampling synchronization, such as a digital protective relay device, an electric energy meter, an electric energy quality monitoring device and the like, thereby providing a convenient solution for the problem that the sampling value internetworking transmission in the prior art depends on the global sampling synchronous source.

The invention discloses a primary cut-out state monitoring method, which comprises following steps: using existing fault recording apparatus and digital protective-relay device in converting station automatic system to record normal divided brake current decay process; using recorded data to calculate circuit breaker opening time; then estimating circuit breaker state according to opening time of circuit breaker and opening time trend in some time.

A digital protective relay for power systems includes a memory location for storing information entered by an operator concerning the operation of the relay. Conventional reports of the relay will include a reference to such operator-entered information. This information will include particular actions taken by the operator relative to the relay, as well as notes made by the operator on particular actions and/or entry of and changes to the relay settings. The entered information can be conveniently retrieved by the operator.

According to one embodiment, a digital protection relay includes an auxiliary transformer (2) which decreases a voltage of an electrical signal from a main circuit transformer (1) to a predetermined voltage; a detection resistance circuit (20) including a Π-type or T-type circuit including an input connected to an output of the auxiliary transformer (2); an analog detection circuit (3) which is connected to an output of the detection resistance circuit (20) and detects a quantity of electricity of an electrical signal from the auxiliary transformer (2); an A/D conversion circuit (4) connected to the analog detection circuit (3); a central processing device 5 which is connected to the A/D conversion circuit (5) and performs a protection operation; and a trip output contact (9) which is closed by processing of the central processing device (5) and operates an external breaker (21). In the digital protection relay, an input contact terminal 11 for inputting a test signal with a constant voltage from an external test device (13) to the analog detection circuit (3) as a signal corresponding to an output of the auxiliary transformer (2) is provided between the detection resistance circuit (20) and the analog detection circuit (3).

Provided is a high-precision and highly functional digital protective relay device and a data transmission device for a digital protective relay device, by enabling transmission of large amounts of system electrical quantity data. The data transmission device for a digital protective relay device, the transmission device comprising: an analog/digital conversion portion 6, which, after sampling a system electrical quantity signal acquired from an electric power system at m times the fundamental frequency f0 (m>12) thereof, performs conversion into n-bit digital data (n>12); a data processing portion 7, which converts m sampling data of n bits with frequency m·f0, obtained by the analog/digital conversion portion, into k sampling data with frequency k·f0 (k≦m) at or below the former frequency; and a transmitting portion 8, which transmits k sampling data obtained by the data processing portion to another protective relay device in a prescribed transmission format.

A visual dynamic monitoring system for operating states of a protective relay system, which is applied to a computer based relay includes: collecting information of a voltage input circuit & a current input circuit and internal hardware & software of protection relay, as well as a tripping and closing circuit, to obtain real-time informations completely reflecting operating states of the protective relay system; analytically calculating the real-time information mentioned above according to the designed protection principle, forming logical relations having a time sequential characteristic among the real-time information with a result by the analytically calculating; and dynamically displaying the operating states of the protective relay system, so as to providing a supporting data for implementing an evaluation of the operating states of the protective relay system.

The system is used in a distance-type protective relay which includes a calculation circuit responsive to voltage and current values from a power line to produce a quantity which is analogous to the distance between the relay and a fault on the line, referred to as an m quantity. This quantity is then applied to a distance element/circuit for comparison of said quantity with a setting reach value for a zone one distance protection to determine whether the fault is within zone one protection. The system includes a filter circuit which filters the quantity before it reaches the distance element, resulting in a smoothing of said quantity and rejection of noise therefrom. The system further includes a control circuit which determines whether the filter is to be used in the system in a particular situation, depending upon whether when the value of the quantity is above a selected percentage of the setting reach value.

It is described a power distribution system for a dynamically positioned vessel. The power distribution system comprises: a plurality of busses (101,103,105,107) comprising a first bus (103) to which a load (123) is connectable; a plurality of switches (109,111,113,115) comprising a first switch (111) and a second switch (113), wherein the plurality of busses is connected via the plurality of switches in an interjacent manner to form a ring (117), the first bus is connected in between the first switch and the second switch. The power distribution system is configured to open the first switch and concurrently open the second switch, if a first current (149) flowing via the first switch in a direction towards the first bus is above a predetermined current threshold for longer than a predetermined time duration and a second current (143); flowing via the second switch in a direction towards the first bus is above the predetermined current threshold for longer than the predetermined time duration, thereby disconnecting the first bus from the ring while all other buses remain connected together. Further a method of power distribution and a vessel are provided.

The invention discloses a start-up protection circuit for an automobile engine, which belongs to the technical field of protection of an automobile starter. The circuit comprises a storage battery, an ignition switch starting gear, a starter, a starting relay, an ignition switch igniting gear, a protective relay and a normally closed oil pressure switch. One output of the storage battery is connected with the starter after sequentially passing through the ignition switch starting gear, the starting relay and the protective relay while the other output of the storage battery is connected with the starter after sequentially passing through the ignition switch starting gear, the normally closed oil pressure switch and the protective relay. According to the start-up protection circuit for the automobile engine provided by the invention, the starter is powered off automatically after the starter starts successfully, so that the starter is protected more safely.

In a digital protection relay with a time sync function, the sampling timing of which is specified based on a reference timing transmitted from a time signal generator to a time sync unit, with a determination value. The time sync unit includes a reception circuit that receives a discrimination code and time data transmitted from the time signal generator, a code discrimination circuit that discriminates the reference timing on condition that the received discrimination code coincides with a desired code, a time calculation circuit that calculates the sampling timing on the basis of the discriminated reference timing and the time data, and a sampling sync circuit that specifies the sampling timing of a digital quantity of electricity on the basis of the calculated sampling timing.

The invention discloses a verification system of grounding direction protective relays; a secondary side of a zero sequence voltage transformer in the verification system is connected with a first wiring terminal and a third wiring terminal of a plug-in; an A-phase end and an N-phase end of a verification instrument voltage channel are respectively connected with a plurality of voltage coils of verified relays through a second wiring terminal and a fourth wiring terminal of the plug-in, and the phase end and the coil have same polarity; a voltage meter is connected in parallel with the A-phase end and the N-phase end of the verification instrument voltage channel; a plurality of zero sequence current transformers and ammeters are connected in series in sequence between the A-phase end and the N-phase end of the verification instrument voltage channel, and have same polarity; a plurality of output ends of the zero sequence current transformers are respectively connected in sequence with the plurality of current coils of the verified relays, and the output ends and the coils have same polarity. The verification system can simultaneously verify all grounding direction protective relays of one busbar; the zero sequence current transformers and the zero sequence voltage transformers are connected in the system; wiring correctness can be verified in the verification process, thereby reducing labor intensity of the verification work, and improving verification efficiency.

Disclosed is a remote communication system and method. A remote communication system includes a digital protection relay and a remote monitoring system. The digital protection relay stores and maintains fault indices for identifying a predetermined number of faults that have occurred, fault time tags corresponding to the fault indices and fault data corresponding to the fault indices. The remote monitoring system sets a fault index, a fault time tag, a fault data block size to be communicated at a time and a fault data block index for specifying a fault data block to be communicated, and requests the digital protection relay of a fault data block.

A device and a method for processing an input data of an protective relay, even in case that data stored in an accumulation buffer of the protective relay is damaged due to noises, etc., that can recover it and carry out a normal measurement are provided, the invention includes a digital signal processing part comprising inputting a sampled digital data to a digital signal processing part, counting and accumulating frequency of the inputted data, comparing the accumulated value with a value of a period, inputting a value of an update accumulation buffer to a measurement accumulation buffer and initializing the update accumulation buffer if the counted accumulation frequency is equal to the value of one period; and performing an RDFT (Recursive Discrete Fourier Transform) operation on the inputted digital data to dually buffering the measurement accumulation buffer and the update accumulation buffer.