JP3082224B2 - Composite protection relay - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a composite protection relay used for a high-voltage switchboard, and measures each phase current, interphase voltage, and power factor in a three-phase power supply line. In addition, the present invention relates to a composite protection relay that collects and collects them to obtain active power.

(Prior Art / Problems to be Solved by the Invention) A phase current I can be measured from an overcurrent relay used for detecting an overcurrent in a power supply line, and an undervoltage in the supply line. It is possible to measure the interphase voltage V and the power factor φ from the undervoltage relay used to detect the power, so that it is possible to convert the active power in the power supply line based on the measurement data of each relay. is there.

And, even if the active power is converted based on the data from each of the relays, as a data transmission line for outputting each data to the conversion circuit, the phase current I, the inter-phase voltage V, the power factor φ And at least four data transmission lines are required due to the nature of, and common lines.

By the way, the present inventors have unitized each relay, and housed them in the same case so that they can be arranged collectively on the power supply line, so that each relay is separated from the power supply line. This is a complex type in which the handling of each relay is easier than in the case of individual arrangement, and the measurement unit is further arranged in the case, so that the data from each relay unit is collectively collected by the communication unit. Developing protective relays.

In this case, in order to perform data transmission between each relay unit and the communication unit individually, we considered connecting them with individual data transmission lines. There is room for

In view of the above, an object of the present invention is to simplify a data transmission line between each relay unit and a communication unit for a composite protection relay for obtaining active power in a three-phase power supply line.

(Means for Solving the Problems) In order to achieve such an object, in the present invention, in addition to a function of detecting and protecting an overcurrent in the three-phase power supply line, each of the three-phase power supply line An overcurrent relay unit having a function of measuring the phase current and outputting the measurement result to the outside as encoded data,
In addition to the function of detecting and protecting the undervoltage in the three-phase power supply line, the lack of a function of measuring the interphase voltage and the power factor in the three-phase power supply line and outputting the measurement result to the outside as encoded data is also insufficient. A voltage relay unit and a communication unit that is connected to each of the relay units via a common data transmission line and obtains active power based on a plurality of encoded data individually transmitted from each of the relay units. And a composite protection relay housed in the same case.

(Operation) Encoded data relating to the phase current measured by the overcurrent relay unit and the inter-phase voltage and power factor measured by the undervoltage relay unit are individually transmitted from the common data transmission line to the communication unit. .

The communication unit captures each data transmitted via the data transmission line, and converts and measures active power based on the captured data.

Each element required to measure the active power of such a three-phase power supply line is housed in a case. Simplification can be achieved as compared with the case where individual lines are provided.

In addition, since a common data transmission line is used for data transmission from each relay unit to the communication unit, the number of data transmission lines can be reduced as compared with the case where individual data transmission lines are used as in the past. And reduce waste.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a use state of a combined protection relay according to an embodiment of the present invention in a power supply line, and FIG. 2 is a schematic block diagram of the combined protection relay.

In FIG. 1, this composite protection relay 2 houses a ground fault relay unit GR, an overcurrent relay unit OCR, an undervoltage relay unit UVR, and a serial interface unit I / F as a communication unit in the same case. It is configured. However, specific configurations of the case and each unit, such as a panel shape, are not shown.

In this combined protection relay 2, the ground fault relay unit GR via the zero-phase current transformer ZCT, the overcurrent relay unit OCR via the current transformer CT via the three-phase power supply line 4, Voltage relay unit UVR is an instrument transformer PT
Via the three-phase voltage and current components, respectively, and with the captured voltage and current components, the overcurrent relay unit OCR detects overcurrent and measures the current of each phase of R, S, and T. In the case of the ground fault relay unit GR, the ground fault detection and the measurement of the zero-phase current are performed, and in the case of the undervoltage relay unit UVR, the undervoltage detection, the voltage between the phases, and the power factor are measured.

Each of these relay units encodes the detected and measured data, and then performs serial processing on the serial interface unit I / O via the common data transmission line 6.
Transmit to F. Serial interface unit I / F
Collectively collects the coded data from each of the relay units transmitted through the data transmission line 6 and determines which of the relay units the coded data is from, or The encoded data is transmitted to an external terminal.

As described with reference to FIG. 2, the ground fault relay unit GR includes an input transformer 8a having a primary side connected to a zero-phase current transformer ZCT, an over-input protection circuit 8b, switching between self-diagnosis / manual test, and setting. It has a processing circuit 8c, a CPU 8d, a data transmission circuit 8e, and a connector 8f for performing various processes required for detecting a ground fault, such as value level switching, a filter, full-wave rectification, and operation determination. Overcurrent relay unit OCR
Are input transformers 10aR, 10aS, 10aT whose primary side is connected to each current transformer CT, over-input protection circuits 10bR, 10bS, 10b.
T, a processing circuit 10c, a CPU 10d, and a data transmission circuit 10 that perform processing necessary for detecting various overcurrents such as switching of self-diagnosis / manual test, switching of set value level, and timed operation determination.
e, and a connector 10f, and has a function of measuring the current I of each of the R, S, and T phases in addition to the main function of detecting an overcurrent. The undervoltage relay unit UVR is composed of an input transformer 12a whose primary side is connected to the
It has an over-input protection circuit 12b1, 12b2, 12b3, a processing circuit 12c, a CPU 12d, a data transmission circuit 12e, and a connector 12f, which perform processing necessary for various undervoltage detection such as manual test switching and effective value conversion. In addition to the main function of detecting an undervoltage, it has a function of measuring the inter-phase voltage V and power factor φ of RS, ST, and TR.

The serial interface unit I / F includes a communication control circuit 14a and a CPU 14b for controlling communication with the outside, a communication control circuit 14c for controlling communication with a unit in the local station, and a connector 14d. It has a function to convert and measure active power based on data from each of the current relay unit OCR and the undervoltage relay unit UVR.

Note that other detailed configurations of the relay units GR, OCR, UVR, and the serial interface unit I / F, which are not particularly necessary for the description of the embodiment, are omitted for simplification of description. doing.

In the above configuration, each protection relay unit GR, OCR, UVR
Is the zero-phase current transformer ZCT, current transformer CT, and instrument transformer PT
The necessary data is obtained from each output, and each data is encoded by the CPUs 8d to 12d corresponding to each protection relay unit, and the encoded data is transmitted from the respective data transmission circuits 8e to 12e. Output to line 6.

In the serial interface unit I / F,
The coded data transmitted via the data transmission line 6 is input to the CPU 14b via the communication control circuit 14c,
In the PU 14b, the coded data is coded data from any of the protective relay units, and after decoding the content, the data is transmitted to the external terminal side via the communication control circuit 14a. .

And in this case the serial interface unit
The I / F converts the active power based on the data of the phase current I, the inter-phase voltage V, and the power factor φ from each of the overcurrent relay unit OCR and the undervoltage relay unit UVR.

(Effects of the Invention) As is apparent from the above description, according to the present invention, a common protection relay is used in which each relay unit and communication unit are housed in the same case, and a common protection relay is provided from each relay unit. Data is transmitted to the communication unit via the data transmission line, and conversion of active power can be performed using the transmitted data. Therefore, a data transmission line for transmitting data required for measuring active power Can be simplified.

[Brief description of the drawings]

FIG. 1 is a diagram showing a use state of a combined protection relay according to an embodiment of the present invention in a power supply line, and FIG. 2 is a schematic block diagram of the combined protection relay. 2 ... combined protection relay, 4 ... 3-phase power line, 6 ...
… Data transmission line, GR… ground fault relay unit, OCR…
Overcurrent relay unit, UVR …… Undervoltage relay unit, I / F …… Serial interface unit, 8d, 10
d, 12d, 14b ... CPU, 8e, 10e, 12e ... Data transmission circuit, 14
c: Communication control circuit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-202113 (JP, A) JP-A-1-321812 (JP, A) JP-A-60-125133 (JP, A) JP-A-49- 90579 (JP, A) JP-A-49-123078 (JP, A) JP-A-61-46109 (JP, A) JP-A-4-17636 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02H 3/02

Claims (1)

(57) [Claims] 1. A function of detecting and protecting an overcurrent in a three-phase power supply line, a function of measuring each phase current in the three-phase power supply line, and outputting the measurement result to the outside as encoded data. In addition to the overcurrent relay unit having the function of detecting and protecting the undervoltage in the three-phase power supply line, it also measures the interphase voltage and the power factor in the three-phase power supply line and uses the measurement result as encoded data. Undervoltage relay unit having a function of outputting to the outside, based on a plurality of encoded data connected to each of the relay units via a common data transmission line and individually transmitted from each of the relay units A combined protection relay, characterized in that a communication unit for obtaining active power is collectively housed in the same case.