CN104535957A - Measuring accuracy comparison device of intelligent substation - Google Patents

Abstract

The invention proposes a measurement accuracy comparison device for an intelligent substation, including a reference current transformer and a reference voltage transformer, a reference electric energy meter, a current transformer to be tested and a voltage transformer to be measured, a combiner unit, an electric energy meter to be measured, Temperature and humidity measurement unit, data processing unit and host computer; the present invention can detect the measurement error and stability of the electronic transformer in real time, compare the consistency between the electronic electric energy meter and the conventional mechanical electric energy meter, compare the conventional electric energy metering system and the The consistency of the digital electric energy metering system, through data analysis, the change rule of the measurement error affected by the temperature and humidity environment, etc.

Description

A smart substation measurement accuracy comparison device

technical field

The invention relates to the technical field of digital electric energy metering systems, in particular to an intelligent substation measurement accuracy comparison device.

Background technique

Electronic transformers are extremely important primary equipment in smart substations. Electronic transformers have many advantages such as good insulation performance, small volume and quality, safety and environmental protection, good transient characteristics, wide frequency range, and strong anti-interference ability. The direction of technology development. After long-term research and trial operation at home and abroad, electronic transformers have entered the practical stage, and electronic transformers are widely used in various types of power transmission and distribution systems. At present, there are more than 1,000 sets of different types of electronic transformers operating in substations with a voltage level of 35kV to 500kV in China, which has accumulated rich field experience for the research and development, manufacturing and application of electronic transformers.

Although the electronic transformer has outstanding advantages, many years of operating experience have shown that the electronic transformer also has many shortcomings, especially unstable operation and low reliability. Electronic transformers are divided into two types: active and passive. The shortcomings of the two types of electronic transformers mainly include:

1) Active electronic transformers exist:

Electronic components such as the signal acquisition unit and its power supply circuit are arranged at the high-voltage end, in a high-voltage, high-current strong interference and high-temperature environment, which puts forward high requirements on the anti-interference performance and life of electronic circuits and components;

The signal acquisition unit and the power supply circuit are at the high-voltage end, cannot be directly grounded, and are in a state of potential suspension, which requires strict anti-interference design of the electronic circuit;

The high-power laser power supply for the signal acquisition unit is expensive and generally has a short service life;

The abnormal output of the electronic transformer is likely to be caused when the laser power supply and the energy-taking coil switch the power supply.

2) There are passive electronic transformers:

The technical problems in the long-term stability of optical materials, sensor head assembly, weak signal modulation and demodulation, temperature drift, vibration displacement, etc. have not yet been fully broken through, and the trial operation effect is not very satisfactory.

In addition, the electric energy meter and metering transformer used in the electric energy metering device used for trade settlement are the metering instruments for national compulsory verification. The "Measurement Law of the People's Republic of China" and its supporting laws and regulations have strict management regulations. The technical standards also have clear technical requirements for electric energy meters, metering transformers, and metering secondary circuits. At present, electric energy metering devices composed of electronic transformers and pure digital electric energy meters have been widely used in digital substations, and their measurement legality has not yet been recognized by the metering supervision department and the majority of electric power companies and electric power users; in digital electric energy metering In the whole system of the device, many links (such as: collector, merging unit, electric energy meter, etc.) can modify the data through software, and the lack of long-term actual operation experience analysis and technical comparison, insufficient technical accumulation, make digital electric energy metering The reliability, fairness and impartiality of the measurement results of the device have been questioned.

On the other hand, there is no systematic comparative study and analysis of the long-term measurement accuracy and stability of electronic transformers, pure digital energy meters, electromagnetic transformers, and conventional energy meters at home and abroad. The resulting situation is:

Lack of technical standards and specifications for measurement and metering systems based on electronic transformers and pure digital energy meters;

There are no rules to follow for the detection and verification of the accurate performance of measuring instruments, and the long-term measurement accuracy and stability of measuring instruments need to be verified;

The technical requirements for testing and testing equipment are not standardized, and the versatility of the equipment is poor.

Therefore, it is of great significance to carry out the research on the measurement accuracy and operation reliability of the transformer.

Contents of the invention

The invention proposes a measurement accuracy comparison device for an intelligent substation, which can assess the measurement accuracy and stability of a digital electric energy metering device for a long time, and capture possible instantaneous measurement defects in the digital electric energy metering device.

Technical scheme of the present invention is realized like this:

A measurement accuracy comparison device for an intelligent substation, comprising:

Reference current transformers and reference voltage transformers for measuring reference currents and reference voltages;

a reference electric energy meter, used to obtain reference electric energy according to the reference current and reference voltage;

The current transformer to be tested and the voltage transformer to be tested are used to measure the current to be measured and the voltage to be measured;

A combiner unit for converting the current to be measured and the voltage to be measured into digital signals;

The electric energy meter to be tested is used to obtain the electric energy to be measured according to the digital signal converted by the combiner unit;

The temperature and humidity measurement unit is used to measure the temperature and humidity information of the environment where the reference current transformer, the reference voltage transformer, the current transformer to be tested and the voltage transformer to be tested are located;

The data processing unit obtains the current transformer to be tested, the voltage transformer to be tested and the electric energy to be measured by comparing the reference current with the current to be measured, the reference voltage with the voltage to be measured, the reference electric energy with the electric energy to be measured, and the temperature and humidity information. Meter stability and measurement error information;

The host computer is used to remotely collect various currents, voltages, electric energy, measurement errors and stability information; perform parameter configuration and time synchronization for each current transformer, voltage transformer, and electric energy meter.

Further, the host is used to set an error threshold to realize an error overrun alarm.

Further, the reference current transformer and the reference voltage transformer are electromagnetic transformers.

Further, the reference electric energy meter is a mechanical electric energy meter.

Further, the current transformer to be tested and the voltage transformer to be tested are electronic transformers.

Further, the electric energy meter to be tested is a digital electric energy meter.

Further, the reference current transformer, the reference voltage transformer and the reference electric energy meter and the data processing unit are connected by cables; the combiner unit is connected to the current transformer to be tested, the voltage transformer to be tested, The electric energy meter to be tested and the data processing unit are connected by optical fiber; the data processing unit is connected to the host by optical fiber; the data processing unit is connected to the electric energy meter to be tested, the reference electric energy meter and the temperature and humidity measurement unit The temperature and humidity measurement unit is connected with the reference current transformer, the reference voltage transformer, the current transformer to be tested and the voltage transformer to be tested by a twisted pair.

Further, the temperature and humidity measurement unit is connected to the data processing unit through an RS485 interface.

Further, the optical fiber communication complies with the DL/T860-9-2 protocol.

Further, the communication of the twisted pair complies with the DL/T645 protocol.

The beneficial effects of the present invention are:

1. In the actual operating environment, use electromagnetic transformers to monitor the measurement errors of various types of electronic transformers in real time, evaluate the measurement accuracy and stability of electronic transformers for a long time, and capture the possible problems of electronic transformers Instantaneous measurement defects;

2. Compare the measurement difference between the conventional electric energy metering system and the pure digital electric energy metering system, verify the consistency of the measurement results of the two metering systems, and provide technical support for the measurement legality demonstration of the pure digital electric energy metering system;

3. Compare the measurement difference between the conventional mechanical energy meter and the digital energy meter, and verify the consistency of the measurement results of the two measurement devices;

4. Through the analysis of the operation data of the electronic transformer, analyze the change rule of its measurement error due to the influence of ambient temperature and humidity;

5. Study the characteristics of the measurement accuracy of various types of electronic transformers changing with the load;

6. Verify that except for transformers and combiner units in smart substations, other links (such as optical fiber transmission circuits and communication networks) will not affect the accuracy of the measurement system.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1, the smart substation measurement accuracy comparison device in this embodiment includes:

Reference current transformers and reference voltage transformers for measuring reference currents and reference voltages;

a reference electric energy meter, used to obtain reference electric energy according to the reference current and reference voltage;

The current transformer to be tested and the voltage transformer to be tested are used to measure the current to be measured and the voltage to be measured;

A combiner unit for converting the current to be measured and the voltage to be measured into digital signals;

The electric energy meter to be tested is used to obtain the electric energy to be measured according to the digital signal converted by the combiner unit;

The temperature and humidity measurement unit is used to measure the temperature and humidity information of the environment where the reference current transformer, the reference voltage transformer, the current transformer to be tested and the voltage transformer to be tested are located;

The data processing unit obtains the current transformer to be tested, the voltage transformer to be tested and the electric energy to be measured by comparing the reference current with the current to be measured, the reference voltage with the voltage to be measured, the reference electric energy with the electric energy to be measured, and the temperature and humidity information. Meter stability and measurement error information;

The host is used to remotely collect various currents, voltages, electric energy, measurement errors and stability information; perform parameter configuration and time synchronization on each current transformer, voltage transformer, and electric energy meter; the host is also used to set error thresholds, Realize error overrun alarm.

In this embodiment, the reference current transformer and the reference voltage transformer are traditional electromagnetic transformers; the reference electric energy meter is a traditional mechanical electric energy meter; the current transformer to be tested and the voltage transformer to be measured It is an electronic transformer, such as a pillar-type electronic transformer; the electric energy meter to be tested is a digital electric energy meter.

The reference current transformer, the reference voltage transformer and the reference electric energy meter and the data processing unit are connected by cables; The meter and the data processing unit are connected through an optical fiber; the data processing unit is connected with the host through an optical fiber; Twisted pair connection; the temperature and humidity measuring unit is connected with the reference current transformer, reference voltage transformer, current transformer to be tested, and voltage transformer to be tested through a twisted pair.

The temperature and humidity measurement unit is connected to the data processing unit through an RS485 interface.

The communication of the optical fiber complies with the DL/T860-9-2 protocol. The communication of the twisted pair complies with the DL/T645 protocol.

When this embodiment is in use, a group of pillar-type electronic current transformers and a group of pillar-type electronic voltage transformers are respectively installed on a line to be tested, and the output of the electronic transformers is connected to the same combiner unit with an optical fiber. The combiner unit follows the DL/T860-9-2 protocol, and transmits the sampled values to the digital energy meter and the data processing unit in a point-to-point or network manner. Correspondingly, an electromagnetic transformer with accurate measurement and good stability is configured on the line to be tested, and the analog output of the electromagnetic transformer is respectively connected to a conventional mechanical energy meter and a data processing unit. Through the RS485 interface, the data processing unit follows the DL/T 645 protocol to collect the electric energy and real-time operating parameters of the digital electric energy meter and the mechanical electric energy meter, and at the same time, it can send information such as parameter configuration and time synchronization to each electric energy meter. The host computer collects various information of the data processing unit through the network, performs operations such as configuration and time synchronization on the data processing unit and each electric energy meter in a remote place, and performs various analysis, statistics, alarms and assessments.

This embodiment can detect the measurement error and stability of the electronic transformer in real time, compare the consistency between the electronic energy meter and the conventional mechanical energy meter, and compare the consistency between the conventional electric energy metering system and the digital electric energy metering system. Data analysis and measurement error are affected by the change law of temperature and humidity environment, etc.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. an intelligent substation measurement accuracy compare device, is characterized in that, comprising:

Reference current mutual inductor and reference voltage mutual inductor, for witness mark electric current and reference voltage;

With reference to electric energy meter, for obtaining with reference to electric flux according to described reference current and reference voltage;

Current transformer to be measured and voltage transformer (VT) to be measured, for measuring electric current to be measured and voltage to be measured;

Combiner unit, for becoming digital signal by electric current to be measured with voltage transitions to be measured;

Electric energy meter to be measured, the digital signal for obtaining according to combiner cell translation obtains electric flux to be measured;

Temperature and humidity measurement unit, for the humiture information of environment residing for witness mark current transformer, reference voltage mutual inductor, current transformer to be measured and voltage transformer (VT) to be measured;

Data processing unit, by reference current and electric current to be measured, reference voltage and voltage to be measured, obtain stability and the measuring error information of current transformer to be measured, voltage transformer (VT) to be measured and electric energy meter to be measured with reference to the contrast of electric flux and electric flux to be measured, humiture information;

Main frame, gathers each electric current, voltage, electric flux, measuring error and stability information for a distant place; To each current transformer, voltage transformer (VT), electric energy meter carry out parameter configuration and pair time.

2. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described main frame is used for step-up error threshold value, and realizing error transfinites alarm.

3. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described reference current mutual inductor and reference voltage mutual inductor are electromagnetic transformer.

4. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described is mechanical power energy meter with reference to electric energy meter.

5. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described current transformer to be measured and voltage transformer (VT) to be measured are electronic mutual inductor.

6. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described electric energy meter to be measured is digitalized electrical energy meter.

7. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described reference current mutual inductor, reference voltage mutual inductor are connected by cable with reference between electric energy meter, data processing unit with described; Described combiner unit and pass through Fiber connection between described current transformer to be measured, voltage transformer (VT) to be measured, electric energy meter to be measured and data processing unit; Fiber connection is passed through between described data processing unit and described main frame; Described data processing unit and described electric energy meter to be measured, pass through twisted pair line connection with reference between electric energy meter and temperature and humidity measurement unit; Described temperature and humidity measurement unit and pass through twisted pair line connection between described reference current mutual inductor, reference voltage mutual inductor, current transformer to be measured and voltage transformer (VT) to be measured.

8. a kind of intelligent substation measurement accuracy compare device as claimed in claim 1, is characterized in that: described temperature and humidity measurement unit is connected by RS485 interface with described data processing unit.

9. a kind of intelligent substation measurement accuracy compare device as claimed in claim 7, is characterized in that: DL/T860-9-2 stipulations are followed in the communication of described optical fiber.

10. a kind of intelligent substation measurement accuracy compare device as claimed in claim 7, is characterized in that: DL/T645 stipulations are followed in the communication of described twisted-pair feeder.