GB/T 20840.9-2017Instrument transformers -- Part 9: Digital interface for instruments transformers (English PDF)

0.1 Overview

This section belongs to the transformer product series standards. It provides application methods for the IEC 61850 series of standards in the field of transformers.

IEC 61850 details the hierarchical substation communications architecture.

By providing instructional materials such as examples and instructions, transformers, relay protection and metering experts are also easily accessible to the IEC 61850 series.

The concepts and methods.

Compared with transformers, digital communication technology is undergoing changes and will continue to develop in the future. Integrate electronic devices directly into mutual inductance this far-reaching change of the instrument still needs to accumulate more experience. Such equipment has not been popularized in the project, and the corresponding norm has not been established.

stand up.

0.2 This section is relative to the IEC 61850 series

The IEC 61850 series of standards is a standard for communication networks and systems intended for power automation. Its most important part stipulates the following content.

---Substation automation system information model.

--- These information models include transformers and other process layer equipment (such as circuit breakers and disconnectors) models, and substation automation systems Systems (such as protective relays and instrumentation) models. The model is defined in IEC 61850-7-3 and 61850-7-4.

--- Communication between intelligent electronic devices (IEDs) in substation automation systems. The abstract model is defined in IEC 61850-7-2.

The mapping of the stack is defined in IEC 61850-8-1 and IEC 61850-9-2.

-- The configuration language used in the configuration of the substation automation system is described in IEC 61850-6.

--- Conformance testing of various IED communication interfaces for power automation systems, including their data models. Conformance testing in IEC 61850-Defined in 10.

The typical situation is that in the traditional system, the IED equipment such as the measurement and control device of the bay layer or the relay protection device, the interface directly passes the analog letter.

The number is connected to the transformer. In this case, the transformer's data model is implemented in the bay device. However, this is not the only way to do law. In the case where the electronic device is directly integrated into the electronic LPIT, the above data model should be implemented in the transformer and the transformer needs to be supported.

Communication Interface. The part of the electronic LPIT that does this work is called a merging unit.

IEC 61850 is a family of standards for the system, leaving many open options to support all current and future scales and voltages Grade substation needs.

In order to reduce the amount of work required for the following tasks, ie to implement in transformers and equipment using digital signals (such as relay protection devices, meter or interoperability between measurement and control devices, this section imposes additional constraints on the implementation of digital communication interfaces.

This section.

--- Replace the GB/T 20840.8-2007 digital solution;

---Provide a transformer product standard with digital interface in accordance with IEC 61850, similar to IEC 62271-3 Switching equipment;

--- Contains "back-to-back compatibility UCA International User Group" "Guidelines for Implementing Transformer Digital Interface Using IEC 61850-9-2";

--- Based on GB/T 25931-2010 time synchronization consistent with IEC/IEEE61850-9-3, 1PPS can also be used (second pulse) and IRIG-B.

0.3 Transformer Digital Interface Overview

An illustrative generalized block diagram of a digital output transformer is shown in FIG. 901 . It represents more from the quadratic converter (SC in Figure 901) for current and/or voltage information, enter a common module labeled "Merge Unit". The merging unit completes all data processing (Including sampling, analog-to-digital conversion, scaling, output formatted messages, etc.) to output time-related digital messages that meet the requirements of this part flow. For the purposes of this section, the merging unit is a physical unit (hardware subsystem) that summarizes and publishes digital output data frames.

Figure 901 General block diagram of digital output electronic LPIT

The merging unit models one or more logical devices containing multiple logical nodes, as shown in FIG. 902 .

Figure 902 A comprehensive diagram of the objects in the merging unit (example)

In the example diagram of the merged cell in Figure 902, current and voltage measurements are modeled using IEC 61850-7-1 using the following logical nodes.

---TCTR class, according to IEC 61850-7-4, instantiating each phase current measurement and neutral point of current transformer three phases respectively Current measurement

--- TVTR class, according to IEC 61850-7-4, instantiated to each phase of the voltage transformer three phase voltage measurement and neutral point respectively Voltage measurement

--- Logical node zero LLN0, contains the sample value control block instance (MSVCB03 and MSVCB04 in this example), this instance controls Simultaneous release of the IEC 61850-9-2 data stream (in this case one is 4000 samples/sec and 1 sample/frame, forming a frame rate per 4000 seconds, another 12800 samples/second and 8 samples/frame, forming a frame rate of 1600 per second, and a control sample the data set of the value of the digital output message content.

The applicable sampling frequency, time synchronization, control block, and data set are defined in this section.

The physical practice of the above concepts may vary depending on the application technique for determining the components required for the actual transformer. One built-in digital data the output electronic LPIT is shown in Figure 903. For more details, see the specific standards in the relevant GB/T 20840 series.

Figure 903 Digital Output Electronic LPIT (Conceptual Example)

All the components shown in FIG. 903 are not absolutely necessary. For clarity, the power source is not shown in the figure. A transformer can be single A physical unit or multiple physical units. For example, it may be a single physical unit per phase that contains a voltage and/or electricity Flow sensors, primary converters, and primary insulation, while all secondary converters and merging units are in a single physical unit of the control room.

The number of inputs and their type (voltage or current) in a single transformer may be different from those shown.

By contrast, an illustrative generalized block diagram of a facility that employs a separate merging unit (SAMU) is shown in FIG. Different from transformer in the merging unit, SAMU is a single product. It accepts the output of the transformer as its input, which conforms to the GB/T 20840 system.

The specification of one of the product standards in the column. The number of inputs and their type (voltage or current) may differ from what is shown in FIG. 904. SAMU and electricity the output generated by the sub-LPIT's built-in merging unit should in principle be indistinguishable from each other (unless SAMU is cascaded with independent transformers and the SAMU's accuracy level leads to lower SAMU output accuracy).

Figure 904 Independent Consolidation Unit

Transformer Part 9. Digital Interface of Instrument Transformer