Pilot project for grid energy storage application in Unified National Power Grid (UNPG)

The MAIN JOURNAL for POWER GRID SPECIALISTS in RUSSIA

2014

DIGEST, February, 2014

38

Innovation

Pilot project for grid energy storage 

application in Unified National 

Power Grid (UNPG) 

Creating intellectual electric network is a global trend. Work in this direction has been successfully 
carried out in many countries. In order to implement a number of elements that will provide UNPG with 
new properties it is necessary to create a technological basis, involving international experience, 
and to ensure in-home development and production of the state-of-art electrical equipment. One of 
these elements is Energy Storage Systems (ESS) based on high power batteries.

Alexander FEDOROV (Александр ФЕДОРОВ),

 Head of infrastructure projects,

 Ivan ILYIN (Иван ИЛЬИН),

 the team leader of special projects, the Department of JSC «FGC UES» infrastructure projects

A

pplication of energy storage systems based on 
lithium-ion batteries is a revolutionary solution 
both in terms of convenience (mobility, com-
pact size, environmental, etc.) and in terms of 

their impact on the planning and power industry ef

fi

 ciency.

For the normal functioning of the uni

fi

 ed power grid 

of the country strict observance of parity between gen-
eration and consumption of power at any given time is 
required. The feasibility of using ESS is the ability to store 
electrical energy generated by power plants in excess dur-
ing minimum load hours and its subsequent output to the 
network during peak hours. This provides a more uniform 

loading of generating facilities during the day and not to 
withdraw a number of power plants at night.

Moreover the use of ESS creates conditions for opti-

mal network infrastructure.

In order to manufacture innovative equipment and de-

velop new cooperation OAO “UES FGC” at the SPIEF 
2010 signed a Memorandum of Understanding with com-
pany Enerl which meant the creation of a network energy 
storage system based on high-power lithium-ion.

In 2011 JSC “FGC UES” in conjunction with “Mobile 

GTPP” (100% subsidiary) embarked on a project on in-
stallation of GESS at UNPG facilities. The analysis se-

lected two spots for possible deployment 
of GESS — 220 kV “Psou” substation in 
Sochi and 220 kV “Volkhov-Severnya” 
substation in St. Petersburg.

Implementation of these projects was 

approved by the Ministry of Energy (Pro-
tocol of 14.11.2010 

№

 414 pro).

GESS COMPOSITION AND FUNCTIONS 

GESS on the base of high-power bat-

teries consists of the following:

• bank of batteries;
• battery control and monitoring system;
• converter equipment;
• switching devices.

Each grid energy storage system at SS 

“Psou” and SS “Volkhov-North” consists 
of 5 containers: 3 containers with batter-
ies, 1 container with conversion equip-

Batteries bank installed at “Psou” substation.

www.eepr.ru

39

ment and 1 container with switching equipment and 
system control equipment. Given the particular sites for 
the installation, the SS “Psou” containers are mounted 
in two tiers, and the SS “Volkhov-North” four contain-
ers arranged in a row. Each container is equipped with 
its own air conditioning and 

fi

 re extinguishing systems 

and freely dismantled wheelbase so to be quickly trans-
ferred to any suitable location along conventional roads 
without special agreement with Road Patrol Service. 
GESS has the following characteristics presented in 
Table.

Energy storage system at SS “Psou” and SS “Volkhov-

North” can be in one of the six internet-preset modes.
1.  “Availability for island mode” — forced (by the sys-

tem operator) transfer of the inverter into voltage con-

trolled mode for rapid (within 400 ms) transfer 
of the system into “island mode.”
2. “Island mode” — dedicated load operation 
under loss of both substation auxiliary power 
supplies.  “Frequency control mode” — net-
work frequency maintenance by GESS load 
shedding or increase.
3. “Power peak smoothing mode” — house 
load peak shaving, i.e. GESS power output dur-
ing maximum consumption and consumption 
during under-consumption. 
4. “Real-time dispatch mode” — ESS dispatch 
control in the whole operation range of ESS.
5. “Charging” Mode — mode of maintaining 
appropriate levels of charge (if none of the 
modes are selected).
6. “Island mode” and  “Availability for island 
mode” are inverter voltage control modes and 
the rest modes of operation are inverter current 
control modes of operation.

Choice of lithium-ion batteries is rooted in a 

number of advantages over batteries with a dif-
ferent chemistry including the most convenient 
structure of rechargeable cells allowing to cre-
ate any required battery capacity and voltage 
range, wide range of admissible discharge cur-
rents allowing to use batteries for a wide range 
of applications in the energy sector, a greater 
number of cycles of use, high speci

fi

 c power 

consumption permitting to create compact and 
powerful energy storage systems and environ-
mental friendliness. 

EQUIPMENT TESTING

In 2011 specialists of JSC «FGC UES» 

jointly with OJSC “Mobile GTPP” and JSC 
“R&D Center at FGC UES” elaborated and 
approved Program and methodology and time-
frames for energy storage systems testing.

The program included a number of param-

eters including frequency measurement of the 
output voltage when working with one or two 

inverters, measurement of the output voltage distortion 
factor, determining the ef

fi

 ciency of inverters, de

fi

 nition 

of the transitional variation of output voltage and inverter 
voltage recovery time, study on the modes of operation as 
a power backup source in frequency control mode, in load 
shaving mode, charge and discharge from the substation 
auxiliary board. It also included checking the functioning 
of the storage in “back-to-back” mode, stability analysis 
for side-by-side operation of two inverters and determin-
ing the overall ef

fi

 ciency of the energy storage.

Based on the successful results of the test it was decid-

ed to modernize the equipment in terms of ESS hardware 
protection improvement, as well as 

fi

 nalization of the in-

terface and installation of additional control panels for the 
operational staff of the substation.

Parameter

Value 

Battery capacity, megawatt hour

2.5* 

AC rated power, megawatt hour

МВт

1.5** 

AC voltage current, three-phase, 50 Hz, kV 

0.4 +10% 

Phasor power factor

>0.95 subject to 

adjustment to +/- 

0.95 (reactive power 

output) 

Harmonic components

<5% THD (total 

harmonic distortion) 

Long-term overload capacity 

125% of rated value  

DC maximum design voltage, V 

DC 1180 V 

DC voltage range, V 

DC 720—1180 V

DC voltage ripple, % 

< 2 

Response time +1 to-1 MW, ms

< 20*** 

Inverter ef

fi

 ciency, % 

> 95 

System ef

fi

 ciency under double inversion, min, % 

88** 

Max stray load losses, % 

<2 of rated power 

Max limit charge/discharge rate (coef

fi

 cient C) 

2 

С

**** 

Rated inactive load, % 

<1 of rated power 

Charge/discharge cycle life 

1600 

Utilization factor (de

fi

 ned as the ratio of hours per 

year when the plant is ready for operation to the 

total number of hours per year  (8760 hours), min: 

• for 

fi

 rst 6 months of pilot operation 

0.96** 

• for the following year of the pilot operation and 

every year of commercial operation 

0.96**

Notes:

*     at the end of life cycle.

**   Warranty parameter

*** Inverter response under frequency control mode C coef

fi

 cient de

fi

 nes 

charge/discharge current relative to battery rated capacity, i.e. 2 C means 

current when the battery is fully discharged in 0.5 hour.

DIGEST, February, 2014

40

Innovation

During commissioning and testing of energy storage 

systems the training of personnel of substations with issu-
ing appropriate certi

fi

 cates were carried out, a set of oper-

ating and maintenance instructions were developed.

By now all energy storage systems test completed and 

Rostekhnadzor permission for putting ESS into operation 
received.

ESS 

fi

 eld of application: 

•  together with or instead of the mobile gas turbine 

power plants (MGTPP);

•  together with or instead of diesel generator sets;
•  oil and gas facilities;
• railway 

facilities;

•  peak load power-consuming industry;
•  regions of Russia, where there is no centralized power 

supply (distributed generation);

•  RF renewables (wind power stations, tidal power sta-

tion etc.);

•  network frequency maintenance;
•  an alternative to construction of generating capacities 

and/or expansion of network infrastructure for supply-
ing electricity to remote areas;

•  essential backup power supply;
•  infrastructure development for electric vehicles.

CONCLUSIONS

As a result of 

fi

 eld test experiences of energy storage 

systems based on 1.5 MW/ 2.5 MWh energy storage ca-
pacity main operating modes have been successfully ex-
plored and serviceability in the following modes has been 
con

fi

 rmed.

Quality improvement.

 ESS can be used to improve 

power quality in case of short-term disturbances in the 
network.

Reliability Improvement

. ESS can be used to provide 

uninterrupted power supply before start of redundant pow-
er supplies (1—10 seconds). In case of outage for more 
than a few seconds ESS is able to generate enough power 
to ensure its continuity, correct deenergizing of equipment 

and/or transition to electricity production in the territory 
of the customer. ESS can ensure uninterrupted power sup-
ply during the time suf

fi

 cient to remedy the outage.

Network power supply reliability improvement.

This function is featured by capability to improve the reli-
ability of power supply to the network side of the meter. 
To implement this function a combination of ESS and die-
sel generator set to compensate short-term power interrup-
tions and to ensure reliability in case of long-term outages 
can be used.

Improvement of reliability of power supply to a 

consumer.

 The main task of this function is to improve 

the reliability of power supply to commercial and indus-
trial consumers. To implement this function a combination 
of ESS and diesel generator set to compensate short-term 
power interruptions and to ensure reliability in case of 
long-term outages can be used.

Sustainability enhancement.

 To maintain stability of 

the power system during large disturbances caused by its 
failures that can be cleared by switchgear tripping, trans-
mitted power should be signi

fi

 cantly below the limit de-

fi

 ned by the static stability. It is known that the maximum 

capacity at which static stability is maintained during 
small disturbances is called a limit of static stability. ESS 
on the base of large capacity batteries can be used on the 
DC side to provide of static and transient stability.

Load curve leveling.

 Load tracking is to ensure bal-

ance of power generation and consumption in a given 
part of the network. ESS is suitable for realization of load 
curve functions as it can quickly and widely change the 
values of the output power, naturally designed to track 
falling and increasing loads. When the load is falling, ESS 
charges, when the load is increasing, ESS discharges. 

Power and frequency balancing.

 Power and frequen-

cy balancing (network load balancing) is intended to com-
pensate short-term 

fl

 uctuations of generated power and 

frequency. ESS usage for frequency stabilization can sig-
ni

fi

 cantly increase the performance of existing regulators.

Voltage regulation

. One of the main tasks carried out 

by ESS is to maintain voltage at a given level 
by generating or absorbing reactive power. To 
stabilize the voltage using ESS is to compen-
sate the reactive resistance network to ensure 
the required indicators of sustainability. Using 
ESS as a voltage regulator reduces the pos-
sibility of voltage sagging and power outage 
occurrence.  This feature is essential during 
peak loads.

Due to the impossibility of reactive power 

transmission over long distances under imple-
mentation of the function, distributed ESS, 
placed at the load lumping, become of par-
ticular importance.

JSC FGC UES continues to work on the 

development of network energy storage units 
and determine the most effective places to in-
stall them.

Five-container ESS. Aeriai view.